File "/usr/lib/pymodules/python2.7/notifier/threads.py", line 82, in _run
    tmp = self._function()
  File "/usr/lib/pymodules/python2.7/notifier/__init__.py", line 104, in __call__
    return self._function( *tmp, **self._kwargs )
  File "/usr/lib/pymodules/python2.7/univention/management/console/modules/udm/__init__.py", line 523, in _thread
    result = module.search( request.options.get( 'container' ), request.options[ 'objectProperty' ], request.options[ 'objectPropertyValue' ], superordinate, scope = request.options.get( 'scope', 'sub' ), hidden=request.options.get('hidden') )
  File "/usr/lib/pymodules/python2.7/univention/management/console/modules/udm/udm_ldap.py", line 184, in wrapper_func
    ret = func( *args, **kwargs )
  File "/usr/lib/pymodules/python2.7/univention/management/console/modules/udm/udm_ldap.py", line 471, in search
    result = self.module.lookup( None, ldap_connection, filter_s, base = container, superordinate = superordinate, scope = scope, sizelimit = sizelimit )

AttributeError: 'NoneType' object has no attribute 'lookup'