a proplem in running OpenERP

hi,

I just installed the OpenERP (on VirtualBox) but can not run it. Below is the detial of the error I recieved.

2013-06-10 09:17:13,363 2341 INFO ? openerp: OpenERP version 8.0dev-20130505-230101
2013-06-10 09:17:13,368 2341 INFO ? openerp: addons paths: /opt/openerp/server/openerp/addons
2013-06-10 09:17:13,370 2341 INFO ? openerp: database hostname: localhost
2013-06-10 09:17:13,371 2341 INFO ? openerp: database port: 5432
2013-06-10 09:17:13,371 2341 INFO ? openerp: database user: omar
2013-06-10 09:17:14,869 2341 CRITICAL ? openerp.modules.module: Couldn't load module web
2013-06-10 09:17:14,872 2341 CRITICAL ? openerp.modules.module: No module named mock
2013-06-10 09:17:14,873 2341 ERROR ? openerp.service: Failed to load server-wide module `web`.
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 "/opt/openerp/server/openerp/service/__init__.py", line 62, in load_server_wide_modules
    openerp.modules.module.load_openerp_module(m)
  File "/opt/openerp/server/openerp/modules/module.py", line 347, in load_openerp_module
    __import__('openerp.addons.' + module_name)
  File "/opt/openerp/server/openerp/modules/module.py", line 83, in load_module
    mod = imp.load_module('openerp.addons.' + module_part, f, path, descr)
  File "/opt/openerp/server/openerp/addons/web/__init__.py", line 3, in <module>
    import cli
  File "/opt/openerp/server/openerp/addons/web/cli/__init__.py", line 1, in <module>
    import test_js
  File "/opt/openerp/server/openerp/addons/web/cli/test_js.py", line 8, in <module>
    import openerp.addons.web.tests
  File "/opt/openerp/server/openerp/addons/web/tests/__init__.py", line 2, in <module>
    from . import test_dataset, test_menu, test_serving_base, test_js
  File "/opt/openerp/server/openerp/addons/web/tests/test_dataset.py", line 2, in <module>
    import mock
ImportError: No module named mock
2013-06-10 09:17:15,040 2341 INFO ? openerp.service.wsgi_server: HTTP service (werkzeug) running on 0.0.0.0:8069
2013-06-10 09:17:15,155 2341 INFO ? openerp: OpenERP server is running, waiting for connections...
Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 551, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 504, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/opt/openerp/server/openerp/service/wsgi_server.py", line 437, in serve
    httpd = werkzeug.serving.make_server(interface, port, application, threaded=threaded)
  File "/usr/lib/python2.7/dist-packages/werkzeug/serving.py", line 399, in make_server
    passthrough_errors, ssl_context)
  File "/usr/lib/python2.7/dist-packages/werkzeug/serving.py", line 331, in __init__
    HTTPServer.__init__(self, (host, int(port)), handler)
  File "/usr/lib/python2.7/SocketServer.py", line 408, in __init__
    self.server_bind()
  File "/usr/lib/python2.7/BaseHTTPServer.py", line 108, in server_bind
    SocketServer.TCPServer.server_bind(self)
  File "/usr/lib/python2.7/SocketServer.py", line 419, in server_bind
    self.socket.bind(self.server_address)
  File "/usr/lib/python2.7/socket.py", line 224, in meth
    return getattr(self._sock,name)(*args)
error: [Errno 98] Address already in use

What do i have to do to resolve this matter.

regards,

Omar