Problems with Starcraft on bnet

Hey everybody. I just wanted to say first that I am a fan of this site and I always find great information here. I'm having a problem that I absolutely can not resolve. I've searched everywhere. I never post threads, but this one has me stumped.

I've got a new ISP AT&T. I play online games such as Unreal Tourn 3, Warcraft 3, and many others with my friends. All of these work, except one. Starcraft is the oldest game I have. I don't know if there's some sort of port block with my new ISP that makes my game so laggy, or if my internet connection is too slow. I've read an article submitted by a college student on the bandwidth that starcraft uses on an internet game, and my upstream and downstream both outperform the unnofficial statistics. but I'm thinking, if another game by the same game manufacturers (warcraft 3) runs perfectly fine, and i've tested starcraft on 3 different computers running XP and Vista, and the computers far surpass the hardware requirements for the game, something's just not right. I love this game, and I'd hate to have to set it down for such a long time. Can someone help me?