LAN Multiplayer problem

[mail2345]

So I have 3 computers on my wireless, A, B and C.
A and C are running Vista, B is running Win7.
A and B can play a game, C can't play a game.
They are all in the same work group.

Any ideas as to what might be wrong?

So after doing alot of searching, it appears to be COMODO at fault. I'm wondering what should I allow though besides(obviously) terranx.exe.

EDIT:
Problem solved by allowing fragmented packets.