Grief syndrome multiplayer

Me and my friend tried to set up multi-player in grief syndrome last night, but it didn't work. We figured the problem was the UDP port, although honestly I'm not sure how the stuff works- we were using 6112, and since that didn't worked we tried a few random others. We didn't delete our save files and back them up, so that could be a problem, but I'm wondering if anyone more knowledgeable could help us out? I believe my friend said the error message she kept getting was "no response from host."