You might try disabling zonealarm temporarily, just to see if that's it. I'm running ZA myself, but I think all I had to do is tell ZA that yes, the dom2.exe was to be allowed to access the internet.
Mmm - if you're running in full screen mode, you might be getting blocked by zonealarm but unable to see it.
Edit: Illwinter has written that 2.13 and 2.12 are compatible, so that shouldn't be it. However, if you do succeed in connecting, you really REALLY want to set yourself up with a 2.12 executable for the game; otherwise the battles you watch are likely to be completely hallucinatory.
IE: You watch a battle, see your pretender destroy the opposing enemy with minimal losses. But the battle report says all your guys died, and your Pretender is waiting to be recalled, like a defective appliance.
