I got it running! 
I read something about GpsGate and just thought its worth a try. Somehow this program can pass the gps-data to b4ppc-apps. I still haven`t got an idea why this is so strange, but I can go on with my work, even if it costs 25 Euro now.
Thanks a lot for your help Erel and Agraham. Maybe some day we will find the failure. (Or not)