--- univention-management-console-web-server	(Revision 53981)
+++ univention-management-console-web-server	(Arbeitskopie)
@@ -244,7 +244,7 @@ 
 				return True
 			CORE.info('UMCP_Dispatcher: check_queue: new request: 0x%x' % (id(queuerequest),))
 
-			if not isinstance(queuerequest.sessionid, basestring) and queuerequest.sessionid is not None:
+			if not isinstance(queuerequest.sessionid, (basestring, type(None))):
 				CORE.process('UMCP_Dispatcher: check_queue: got invalid sessionid: %r' % (queuerequest.sessionid,))
 			if not isinstance(queuerequest.request, umcp.Request):
 				CORE.process('UMCP_Dispatcher: check_queue: got invalid UMCP request: %r' % (queuerequest.request,))
@@ -276,10 +276,10 @@ 
 				# add a small offset to the timeout in order to avoid a mismatch between frontend and backend
 				try:
 					client = SessionClient(timeout = _session_timeout + 5, ip = queuerequest.ip, cookie = queuerequest.cookie)
-				except Exception, e:
-					CORE.process( 'Failed to create UMC connection: %s' % str(e))
+				except umcp.NoSocketError as exc:
+					CORE.process( 'Failed to create UMC connection: %s' % (exc,))
 					response = umcp.Response( queuerequest.request )
-					response.status = httplib.UNAUTHORIZED # set status to unauthorized
+					response.status = httplib.SERVICE_UNAVAILABLE
 					queuerequest.response_queue.put( response )
 					continue