i am trying to install it but it raise the error like even i also tried it with addons path

The `web` module is provided by the addons found in the `openerp-web` project. 
Maybe you forgot to add those addons in your addons_path configuration. 
Traceback (most recent call last):
 File "/home/atul/openerp-8/openerp/service/server.py", line 792, in     load_server_wide_modules
openerp.modules.module.load_openerp_module(m)
File "/home/atul/openerp-8/openerp/modules/module.py", line 357, in load_openerp_module
 getattr(sys.modules['openerp.addons.' + module_name], info['post_load'])()
File "/home/atul/openerp-8/openerp/http.py", line 1142, in wsgi_postload
root = Root()
File "/home/atul/openerp-8/openerp/http.py", line 922, in __init__
self.load_addons()
File "/home/atul/openerp-8/openerp/http.py", line 947, in load_addons
m = __import__('openerp.addons.' + module)
File "/home/atul/openerp-8/openerp/modules/module.py", line 83, in load_module
mod = imp.load_module('openerp.addons.' + module_part, f, path, descr)
File "/home/atul/openerp-8/openerp/addons/magentoerpconnect/__init__.py", line 6, in     <module>
import magento_model
File "/home/atul/openerp-8/openerp/addons/magentoerpconnect/magento_model.py", line 34, in <module>
 from .unit.backend_adapter import GenericAdapter 
 File "/home/atul/openerp-8/openerp/addons/magentoerpconnect/unit/__init__.py", line 5, in <module>
import import_synchronizer 
File "/home/atul/openerp-8/openerp/addons/magentoerpconnect/unit/import_synchronizer.py", line 26, in <module>
from openerp.addons.connector.queue.job import job
File "/home/atul/openerp-8/openerp/addons/connector/queue/__init__.py", line 22, in <module>
import model   
File "/home/atul/openerp-8/openerp/addons/connector/queue/model.py", line 31, in <module>
from .worker import WORKER_TIMEOUT    
File "/home/atul/openerp-8/openerp/addons/connector/queue/worker.py", line 34, in <module>
from openerp.osv.osv import PG_CONCURRENCY_ERRORS_TO_RETRY
ImportError: cannot import name PG_CONCURRENCY_ERRORS_TO_RETRY