Standalone Trac works fine but not with webserver (mod_wsgi)

[arash sami]

Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/web/api.py", line 441, in send_error
    data, 'text/html')
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/web/chrome.py", line 825, in render_template
    message = req.session.pop('chrome.%s.%d' % (type_, i))
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/web/api.py", line 216, in __getattr__
    value = self.callbacks[name](self)
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/web/main.py", line 306, in _get_session
    return Session(self.env, req)
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/web/session.py", line 207, in __init__
    self.get_session(sid)
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/web/session.py", line 228, in get_session
    super(Session, self).get_session(sid, authenticated)
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/web/session.py", line 61, in get_session
    db = self.env.get_db_cnx()
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/env.py", line 329, in get_db_cnx
    return get_read_db(self)
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/db/api.py", line 90, in get_read_db
    return _transaction_local.db or DatabaseManager(env).get_connection()
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/db/api.py", line 152, in get_connection
    return self._cnx_pool.get_cnx(self.timeout or None)
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/db/pool.py", line 227, in get_cnx
    return _backend.get_cnx(self._connector, self._kwargs, timeout)
  File "/usr/lib/python2.6/site-packages/Trac-0.12.3-py2.6.egg/trac/db/pool.py", line 147, in get_cnx
    raise TimeoutError(errmsg)
TimeoutError: Unable to get database connection within 0 seconds. (OperationalError: FATAL:  Ident authentication failed for user "root"
)