Hi Jan ;),
I finally found a solution to my problem: Since the hostname of my Polyspace Server could not be resolved via DNS server, the configuration in the polyspace.conf was misleading. Somehow the information "cpu=[NameOfServer]" resulted in an erroneous start of the deamon process, because the name was unknown. So two Queue Manager were running concurrently. Changeing the line in the config file to "cpu=localhost:12427" fixed the problem. You may also leave out the port number, but I did not try that yet as I was lucky to get it work at last.
Greetings,
Jan