Install two Odoo 10.0c with the same installer in two different LinuxMint.
When I add the product_return_pos(https://www.odoo.com/apps/modules/10.0/product_return_pos/) apps and install:

LinuxMint 1 = Open POS, works correctly with the app

LinuxMint 2 = Open POS, black screen. A detail, when I open the information of the application, the JPG of Overview does not load. As if I did not have permission.

Check the permissions of folders and files,
-rwxr-xr-x
owner user odoo

 LinuxMint 2 (error) Odoo-Server.log

2018-05-22 03:59:05,406 1610 INFO Kachito werkzeug: 192.168.0.4 - - [22/May/2018 03:59:05] "POST /web/dataset/search_read HTTP/1.1" 200 -
2018-05-22 03:59:05,456 1610 INFO Kachito werkzeug: 192.168.0.4 - - [22/May/2018 03:59:05] "GET /product_return_pos/static/description/icon.png HTTP/1.1" 404 -
2018-05-22 03:59:08,200 1610 INFO Kachito werkzeug: 192.168.0.4 - - [22/May/2018 03:59:08] "POST /web/dataset/call_kw/ir.module.module/read HTTP/1.1" 200 -
2018-05-22 03:59:08,264 1610 INFO Kachito werkzeug: 192.168.0.4 - - [22/May/2018 03:59:08] "POST /web/dataset/search_read HTTP/1.1" 200 -
2018-05-22 03:59:08,511 1610 INFO Kachito werkzeug: 192.168.0.4 - - [22/May/2018 03:59:08] "POST /web/dataset/call_kw/ir.module.module.dependency/read HTTP/1.1" 200 -
2018-05-22 03:59:11,599 1610 INFO Kachito odoo.modules.loading: loading 1 modules...
2018-05-22 03:59:11,652 1610 INFO Kachito odoo.modules.loading: 1 modules loaded in 0.05s, 0 queries
2018-05-22 03:59:11,817 1610 INFO Kachito odoo.modules.loading: loading 38 modules...
2018-05-22 03:59:11,931 1610 INFO Kachito odoo.modules.loading: 38 modules loaded in 0.11s, 0 queries
2018-05-22 03:59:11,936 1610 INFO Kachito odoo.modules.loading: loading 39 modules...
2018-05-22 03:59:12,167 1610 INFO Kachito odoo.modules.registry: module product_return_pos: creating or updating database tables
2018-05-22 03:59:12,430 1610 INFO Kachito odoo.modules.loading: loading product_return_pos/views/return.xml
2018-05-22 03:59:12,739 1610 INFO Kachito odoo.modules.loading: loading product_return_pos/views/pos_template.xml
2018-05-22 03:59:12,821 1610 INFO Kachito odoo.addons.base.ir.ir_translation: module product_return_pos: no translation for language es_AR
2018-05-22 03:59:12,925 1610 INFO Kachito odoo.modules.loading: 39 modules loaded in 0.99s, 3 queries
2018-05-22 03:59:13,906 1610 INFO Kachito odoo.modules.loading: Modules loaded.
2018-05-22 03:59:13,911 1610 INFO Kachito odoo.modules.registry: Registry changed, signaling through the database
2018-05-22 03:59:13,914 1610 INFO Kachito odoo.addons.base.res.res_config: getting next operation
2018-05-22 03:59:13,914 1610 INFO Kachito odoo.addons.base.res.res_config: getting next ir.actions.todo()
2018-05-22 03:59:13,919 1610 INFO Kachito odoo.addons.base.res.res_config: next action is None
2018-05-22 03:59:13,920 1610 INFO Kachito odoo.modules.registry: At least one model cache has been invalidated, signaling through the database.
2018-05-22 03:59:13,922 1610 INFO Kachito werkzeug: 192.168.0.4 - - [22/May/2018 03:59:13] "POST /web/dataset/call_button HTTP/1.1" 200 -
2018-05-22 03:59:13,950 1610 INFO Kachito odoo.modules.registry: Invalidating all model caches after database signaling.
2018-05-22 03:59:13,955 1610 INFO Kachito odoo.addons.base.ir.ir_http: Generating routing map
2018-05-22 03:59:15,520 1610 INFO Kachito werkzeug: 192.168.0.4 - - [22/May/2018 03:59:15] "GET /web HTTP/1.1" 200 -
2018-05-22 03:59:16,284 1610 INFO Kachito werkzeug: 192.168.0.4 - - [22/May/2018 03:59:16] "POST /web/dataset/call HTTP/1.1" 200 -
2018-05-22 03:59:16,297 1610 INFO Kachito werkzeug: 192.168.0.4 - - [22/May/2018 03:59:16] "GET /web/webclient/qweb?mods=web,web_kanban,base,bus,web_tour,mail,report,product,web_planner,account,account_bank_statement_import,barcodes,point_of_sale,web_editor,web_settings_dashboard,sales_team,sale,sale_stock,stock,base_import,web_calendar,portal,payment,web_diagram,l10n_ar,payment_transfer,web_kanban_gauge HTTP/1.1" 200 -

Then, enable log_level debug and Product_Return_Pos started to work.

When I wanted to enable another module "order_reprinting_pos" it did not work.

Log in mode Debug

2018-05-22 05:19:27,204 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:27,241 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:27] "POST /web/dataset/search_read HTTP/1.1" 200 -
2018-05-22 05:19:37,283 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:37,299 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:37] "POST /web/dataset/search_read HTTP/1.1" 200 -
2018-05-22 05:19:37,337 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:37,341 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:37,342 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:37] "GET /account_check_printing/static/description/icon.png HTTP/1.1" 404 -
2018-05-22 05:19:37,345 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:37] "GET /order_reprinting_pos/static/description/icon.png HTTP/1.1" 404 -
2018-05-22 05:19:50,418 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,420 16677 DEBUG Kachito_ini odoo.api: call ir.module.module(293,).read([u'menus_by_module', u'demo', u'views_by_module', u'description_html', u'author', u'installed_version', u'icon_image', u'application', u'state', u'website', u'reports_by_module', u'name', u'license', u'summary', u'dependencies_id', u'shortdesc', u'category_id', u'display_name', u'__last_update'])
2018-05-22 05:19:50,446 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "POST /web/dataset/call_kw/ir.module.module/read HTTP/1.1" 200 -
2018-05-22 05:19:50,518 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,520 16677 DEBUG Kachito_ini odoo.api: call ir.module.category().name_search(u'', [])
2018-05-22 05:19:50,535 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "POST /web/dataset/call_kw/ir.module.category/name_search HTTP/1.1" 200 -
2018-05-22 05:19:50,575 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,579 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "POST /web/dataset/search_read HTTP/1.1" 200 -
2018-05-22 05:19:50,606 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,607 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,608 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,616 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,617 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "GET /order_reprinting_pos/static/description/order-button.png HTTP/1.1" 404 -
2018-05-22 05:19:50,617 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,620 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "GET /order_reprinting_pos/static/description/orders-list.png HTTP/1.1" 404 -
2018-05-22 05:19:50,623 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "GET /order_reprinting_pos/static/description/old-receipt.png HTTP/1.1" 404 -
2018-05-22 05:19:50,623 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "GET /order_reprinting_pos/static/description/order-re-pdf.png HTTP/1.1" 404 -
2018-05-22 05:19:50,625 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "GET /order_reprinting_pos/static/description/cybro_logo.png HTTP/1.1" 404 -
2018-05-22 05:19:50,791 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,793 16677 DEBUG Kachito_ini odoo.api: call ir.module.module.dependency().fields_get()
2018-05-22 05:19:50,795 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "POST /web/dataset/call_kw/ir.module.module.dependency/fields_get HTTP/1.1" 200 -
2018-05-22 05:19:50,979 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:19:50,981 16677 DEBUG Kachito_ini odoo.api: call ir.module.module.dependency(568,).read([u'name', u'state'])
2018-05-22 05:19:50,987 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:50] "POST /web/dataset/call_kw/ir.module.module.dependency/read HTTP/1.1" 200 -
2018-05-22 05:19:58,508 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:19:58] "POST /longpolling/poll HTTP/1.1" 200 -
2018-05-22 05:19:58,533 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:20:02,716 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 10 -> 10] [Cache - 18 -> 18]
2018-05-22 05:20:02,718 16677 DEBUG Kachito_ini odoo.api: call ir.module.module(293,).button_immediate_install()
2018-05-22 05:20:03,019 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess load registry signaling: [Registry: 10] [Cache: 18]
2018-05-22 05:20:03,022 16677 INFO Kachito_ini odoo.modules.loading: loading 1 modules...
2018-05-22 05:20:03,022 16677 DEBUG Kachito_ini odoo.modules.loading: loading module base (1/1)
2018-05-22 05:20:03,049 16677 INFO Kachito_ini odoo.modules.loading: 1 modules loaded in 0.03s, 0 queries
2018-05-22 05:20:03,148 16677 DEBUG Kachito_ini odoo.modules.loading: Updating graph with 38 more modules
2018-05-22 05:20:03,149 16677 INFO Kachito_ini odoo.modules.loading: loading 39 modules...
2018-05-22 05:20:03,149 16677 DEBUG Kachito_ini odoo.modules.loading: loading module auth_crypt (2/39)
2018-05-22 05:20:03,155 16677 DEBUG Kachito_ini odoo.modules.loading: loading module decimal_precision (3/39)
2018-05-22 05:20:03,156 16677 DEBUG Kachito_ini odoo.modules.loading: loading module web (4/39)
2018-05-22 05:20:03,156 16677 DEBUG Kachito_ini odoo.modules.loading: loading module barcodes (5/39)
2018-05-22 05:20:03,158 16677 DEBUG Kachito_ini odoo.modules.loading: loading module bus (6/39)
2018-05-22 05:20:03,159 16677 DEBUG Kachito_ini odoo.modules.loading: loading module web_calendar (7/39)
2018-05-22 05:20:03,159 16677 DEBUG Kachito_ini odoo.modules.loading: loading module web_diagram (8/39)
2018-05-22 05:20:03,159 16677 DEBUG Kachito_ini odoo.modules.loading: loading module web_editor (9/39)
2018-05-22 05:20:03,166 16677 DEBUG Kachito_ini odoo.modules.loading: loading module web_kanban (10/39)
2018-05-22 05:20:03,166 16677 DEBUG Kachito_ini odoo.modules.loading: loading module web_planner (11/39)
2018-05-22 05:20:03,166 16677 DEBUG Kachito_ini odoo.modules.loading: loading module web_tour (12/39)
2018-05-22 05:20:03,167 16677 DEBUG Kachito_ini odoo.modules.loading: loading module base_import (13/39)
2018-05-22 05:20:03,171 16677 DEBUG Kachito_ini odoo.modules.loading: loading module base_setup (14/39)
2018-05-22 05:20:03,172 16677 DEBUG Kachito_ini odoo.modules.loading: loading module web_kanban_gauge (15/39)
2018-05-22 05:20:03,172 16677 DEBUG Kachito_ini odoo.modules.loading: loading module web_settings_dashboard (16/39)
2018-05-22 05:20:03,172 16677 DEBUG Kachito_ini odoo.modules.loading: loading module mail (17/39)
2018-05-22 05:20:03,179 16677 DEBUG Kachito_ini odoo.modules.loading: loading module report (18/39)
2018-05-22 05:20:03,181 16677 DEBUG Kachito_ini odoo.modules.loading: loading module analytic (19/39)
2018-05-22 05:20:03,182 16677 DEBUG Kachito_ini odoo.modules.loading: loading module auth_signup (20/39)
2018-05-22 05:20:03,183 16677 DEBUG Kachito_ini odoo.modules.loading: loading module fetchmail (21/39)
2018-05-22 05:20:03,184 16677 DEBUG Kachito_ini odoo.modules.loading: loading module product (22/39)
2018-05-22 05:20:03,189 16677 DEBUG Kachito_ini odoo.modules.loading: loading module sales_team (23/39)
2018-05-22 05:20:03,190 16677 DEBUG Kachito_ini odoo.modules.loading: loading module account (24/39)
2018-05-22 05:20:03,211 16677 DEBUG Kachito_ini odoo.modules.loading: loading module portal (25/39)
2018-05-22 05:20:03,212 16677 DEBUG Kachito_ini odoo.modules.loading: loading module procurement (26/39)
2018-05-22 05:20:03,213 16677 DEBUG Kachito_ini odoo.modules.loading: loading module account_bank_statement_import (27/39)
2018-05-22 05:20:03,215 16677 DEBUG Kachito_ini odoo.modules.loading: loading module l10n_ar (28/39)
2018-05-22 05:20:03,215 16677 DEBUG Kachito_ini odoo.modules.loading: loading module payment (29/39)
2018-05-22 05:20:03,217 16677 DEBUG Kachito_ini odoo.modules.loading: loading module sale (30/39)
2018-05-22 05:20:03,222 16677 DEBUG Kachito_ini odoo.modules.loading: loading module stock (31/39)
2018-05-22 05:20:03,232 16677 DEBUG Kachito_ini odoo.modules.loading: loading module payment_transfer (32/39)
2018-05-22 05:20:03,233 16677 DEBUG Kachito_ini odoo.modules.loading: loading module portal_sale (33/39)
2018-05-22 05:20:03,234 16677 DEBUG Kachito_ini odoo.modules.loading: loading module stock_account (34/39)
2018-05-22 05:20:03,237 16677 DEBUG Kachito_ini odoo.modules.loading: loading module point_of_sale (35/39)
2018-05-22 05:20:03,244 16677 DEBUG Kachito_ini odoo.modules.loading: loading module sale_stock (36/39)
2018-05-22 05:20:03,248 16677 DEBUG Kachito_ini odoo.modules.loading: loading module portal_stock (37/39)
2018-05-22 05:20:03,248 16677 DEBUG Kachito_ini odoo.modules.loading: loading module procurement_jit (38/39)
2018-05-22 05:20:03,249 16677 DEBUG Kachito_ini odoo.modules.loading: loading module product_return_pos (39/39)
2018-05-22 05:20:03,249 16677 INFO Kachito_ini odoo.modules.loading: 39 modules loaded in 0.10s, 0 queries
2018-05-22 05:20:03,252 16677 DEBUG Kachito_ini odoo.modules.loading: Updating graph with 1 more modules
2018-05-22 05:20:03,253 16677 INFO Kachito_ini odoo.modules.loading: loading 40 modules...
2018-05-22 05:20:03,253 16677 DEBUG Kachito_ini odoo.modules.loading: loading module order_reprinting_pos (37/40)
2018-05-22 05:20:03,449 16677 INFO Kachito_ini odoo.modules.registry: module order_reprinting_pos: creating or updating database tables
2018-05-22 05:20:03,476 16677 DEBUG Kachito_ini odoo.models.schema: Table 'pos_order': added column 'currency_id' with definition=int4
2018-05-22 05:20:03,478 16677 DEBUG Kachito_ini odoo.models: Table 'pos_order': setting default value of new column currency_id to 20
2018-05-22 05:20:03,481 16677 DEBUG Kachito_ini odoo.models.schema: Table 'pos_order': added foreign key 'currency_id' with definition=REFERENCES "res_currency" ON DELETE set null
2018-05-22 05:20:03,481 16677 DEBUG Kachito_ini odoo.models.schema: Table 'pos_order': column 'currency_id': added a NOT NULL constraint
2018-05-22 05:20:03,719 16677 INFO Kachito_ini odoo.modules.loading: loading order_reprinting_pos/report/receipt_report.xml
2018-05-22 05:20:03,800 16677 INFO Kachito_ini odoo.modules.loading: loading order_reprinting_pos/views/pos_template.xml
2018-05-22 05:20:03,837 16677 INFO Kachito_ini odoo.modules.loading: loading order_reprinting_pos/views/point_of_sale_report.xml
2018-05-22 05:20:03,922 16677 INFO Kachito_ini odoo.addons.base.ir.ir_translation: module order_reprinting_pos: no translation for language es_AR
2018-05-22 05:20:03,991 16677 INFO Kachito_ini odoo.modules.loading: 40 modules loaded in 0.74s, 0 queries
2018-05-22 05:20:04,227 16677 DEBUG Kachito_ini odoo.models: column web is in the table ir_module_module but not in the corresponding object ir.module.module
2018-05-22 05:20:04,328 16677 DEBUG Kachito_ini odoo.models: column delay is in the table sale_report but not in the corresponding object sale.report
2018-05-22 05:20:04,340 16677 DEBUG Kachito_ini odoo.models: column account_analytic_id is in the table account_invoice_report but not in the corresponding object account.invoice.report
2018-05-22 05:20:04,587 16677 INFO Kachito_ini odoo.modules.loading: Modules loaded.
2018-05-22 05:20:04,591 16677 INFO Kachito_ini odoo.modules.registry: Registry changed, signaling through the database
2018-05-22 05:20:04,592 16677 INFO Kachito_ini odoo.addons.base.res.res_config: getting next operation
2018-05-22 05:20:04,592 16677 INFO Kachito_ini odoo.addons.base.res.res_config: getting next ir.actions.todo()
2018-05-22 05:20:04,596 16677 INFO Kachito_ini odoo.addons.base.res.res_config: next action is None
2018-05-22 05:20:04,596 16677 INFO Kachito_ini odoo.modules.registry: At least one model cache has been invalidated, signaling through the database.
2018-05-22 05:20:04,598 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:20:04] "POST /web/dataset/call_button HTTP/1.1" 200 -
2018-05-22 05:20:04,632 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 11 -> 11] [Cache - 18 -> 19]
2018-05-22 05:20:04,633 16677 INFO Kachito_ini odoo.modules.registry: Invalidating all model caches after database signaling.
2018-05-22 05:20:04,635 16677 INFO Kachito_ini odoo.addons.base.ir.ir_http: Generating routing map
2018-05-22 05:20:07,398 16677 INFO Kachito_ini odoo.models.unlink: User #1 deleted ir.attachment records with IDs: [590, 589]
2018-05-22 05:20:09,011 16677 INFO Kachito_ini odoo.models.unlink: User #1 deleted ir.attachment records with IDs: [586]
2018-05-22 05:20:09,251 16677 INFO Kachito_ini odoo.modules.registry: At least one model cache has been invalidated, signaling through the database.
2018-05-22 05:20:09,282 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:20:09] "GET /web HTTP/1.1" 200 -
2018-05-22 05:20:09,338 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 11 -> 11] [Cache - 20 -> 20]
2018-05-22 05:20:09,340 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 11 -> 11] [Cache - 20 -> 20]
2018-05-22 05:20:09,349 16677 DEBUG Kachito_ini odoo.modules.registry: Multiprocess signaling check: [Registry - 11 -> 11] [Cache - 20 -> 20]
2018-05-22 05:20:09,396 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:20:09] "GET /web/content/592-a9db743/web.assets_backend.1.css HTTP/1.1" 200 -
2018-05-22 05:20:09,417 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:20:09] "GET /web/content/591-a9db743/web.assets_backend.0.css HTTP/1.1" 200 -
2018-05-22 05:20:09,480 16677 INFO Kachito_ini werkzeug: 192.168.0.4 - - [22/May/2018 05:20:09] "GET /web/content/593-a9db743/web.assets_backend.js HTTP/1.1" 200 -

Error:
"GET /order_reprinting_pos/static/description/icon.png HTTP/1.1" 404 -
At least one model cache has been invalidated, signaling through the database.
odoo.modules.registry: Invalidating all model caches after database signaling.

none of the two currently work

any help is welcome !!

Thank you!.

PD; Excuse my english, I use the google translator