I had the same problem.
Here are the UDP ports I unblocked before realizing it was my Peer Guardian that was not letting my computer talk to the GameSpy Network...
Remote:
67,53,1900,1781,1779,1777,1775,2943,2941,2939,2937
,2450,3625,68,4264,4262,4260,4258,1883,1881,1879,1
877,2869,4303,4305,4307,4309,1050,1048,1046,1044,6
8,4198,96,4194,4192,
Note: there are more ports that I didn´t bother writing down b/c I realized it was my Peer Guardian app.
Local: 53,67,68,1900,2943,
I hope that helps anyone.