Hello, in Odoo 8 I tried to replace the file addons/stock/product.py by the same file with a new line.
I execute my line " python /etc/bin/odoo -c ... -u stock " to update stock
It does an assertion error, like if the module try to install a new report but there is an existing one : 

AssertionError: The report "report.stock.product.history" already exists.

Then i don't do anything but refresh the page, and Odoo is showed without CSS but the folling errors:

 Could not get content for /web/static/lib/cleditor/jquery.cleditor.css defined in bundle 'web.assets_backend'.
 Could not get content for /web/static/lib/jquery.textext/jquery.textext.css defined in bundle 'web.assets_backend'.
 Could not get content for /web/static/lib/select2/select2.css defined in bundle 'web.assets_backend'.
 Could not get content for /web/static/lib/bootstrap/css/bootstrap.css defined in bundle 'web.assets_backend'.
 Could not get content for /web/static/lib/jquery.ui.bootstrap/css/custom-theme/jquery-ui-1.9.0.custom.css defined in bundle 'web.assets_backend'.
 Could not get content for /web/static/lib/jquery.ui.timepicker/css/jquery-ui-timepicker-addon.css defined in bundle 'web.assets_backend'.
 Could not get content for /web/static/lib/jquery.ui.notify/css/ui.notify.css defined in bundle 'web.assets_backend'.
 Could not get content for /web/static/src/css/base.css defined in bundle 'web.assets_backend'.
 Could not get content for /web/static/src/css/data_export.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_calendar/static/src/css/web_fullcalendar.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_calendar/static/lib/fullcalendar/css/fullcalendar.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_diagram/static/src/css/base_diagram.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_gantt/static/src/css/gantt.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_gantt/static/lib/dhtmlxGantt/codebase/dhtmlxgantt.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_graph/static/src/css/graph.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_graph/static/src/css/nv.d3.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_kanban/static/src/css/kanban.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_searchbar_full_width/static/src/css/web_searchbar_full_width.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_sheet_full_width/static/src/css/web_sheet_full_width.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_tests/static/src/css/web_tests.css defined in bundle 'web.assets_backend'.
 Could not get content for /web_view_editor/static/src/css/view_editor.css defined in bundle 'web.assets_backend'.

I tried to put another file exactly like the original file, or edit with nano the file to delete changes, but no changes.

I tried to do sudo service odoo start, i acceded to the database/login view but after connection there is the same problem...