I seem to be having the same problem, Warcraft III (ROC)
What I have tried:
Re-Re-installing,
Resetting Router,
Turning Firewall Off,
Turning UAC Off,
Update to latest patch,
Use BattleNet Registry Fix (reset battle.net servers to defaults),
Third Party WC3
Fixer
Not completely sure if this would be a problem, Could some background service in Windows 7 be using a port required for Battle.net?
From my understanding, underneath .NET Remoting uses a TCP connection, which should take the use of a port (or two). So, could there be some service in the back ground using a Remoting object using up a special port. (Just an idea, could be a load of bollocks, or some other error...)