code: def error(self, interface_id, errorcode, msg):
          
          LOG.debug("RPCFunctions.error: interface_id = %s, errorcode = %i, message = %s" % (
              interface_id, int(errorcode), str(msg)))
          if self.systemcallback:
              self.systemcallback('error', interface_id, errorcode, msg)
          return True
docs: When some error occurs the CCU / Homegear will send it's error message here