Who can help me?
The problem is that i cant host anymore after the patch 1.03.
Befor the patch (1.02) we didnt have a problem.
I reinstalled the game and try to host wihtout the patch and there was no problem. Then i update the patch and it was the same problem again, we do not get a server online...who else have this problem?

a coop server won't work, there are problems with the 1.3 patch.
Otherwise make sure your windows firewall has the allow echo request box clicked in advanced settings.