I'm getting similar problems on my crappy work system as well, I've tried Build 200 and 204 of forge, as well as 191 of FML, same issue regardless. However there is no problem with running the game vanilla, so this problem only occurs after forge and/or FML is introduced. I have tried copying the lwgl files into my 1.3.2 installation from the vanilla version just in case, but no joy.
Also, for the record I do not get this problem with my older 1.3.1 install, but that was using modloader as there was no alternative at the time I made it.