Stuck at BTTF login screen
 

I'm trying to play BTTF episode 2, but I can't get past the login screen. Whenever I start the game, I have a few seconds when the launcher will respond to input, but then the login screen freezes before I can enter my full username/password. It doesn't freeze if I'm disconnected from the Internet, though.

I'm running 32-bit XP SP3 and just updated my graphics drivers to the latest version. I also made sure to add an exception to my firewall.