I've searched everywhere for this specific problem, so apologies if this has already been answered.

My housemate installed Demigod via impulse, using my profile, so we could play each other offline. We've set up the ports for each ip address between 6002 and 6200 (Linksys wireless G 2.4 Gig.)I'm using Vista 64 sp 2, and my housemate is on windows 7.

When we launch a game via the lobby, it starts to load the game, but then comes up with the error message 'Invalid game state - critical error' and counts down and ends the game.

We both reinstalled Demigod via impulse, so had to wait for another download, both ran the game via the .exe file, it worked once, and then the same problem occurred when we started another game. We've tried both running it through impulse, but the same problem occurs. I also tried running my housemates .exe through Vista 64 sp 2 compatibility mode, but this also didn't work. I also tried using different port ranges, but surely this is for online play...besides, that didn't work either.

I've been playing Demigod for several months, and have been waiting a long time to finally have a lan game, so this is very frustrating, any ideas ?

EDIT: Forgot to mention, firewall and antivirus were turned off