TGE problems with x64 Vista Ultimate Service Pack 1

I've been having problems with TGE lately. I can get the engine started up in tutorial base, but when I try to load a mission it gives me an error message of the program not working properly and quits out. It only happens when I go to the World Editor. All the other features work fine.

Before I had SP2 installed it worked fine (on SP1 and before that). Now I can't get it to work right. Anyone know if there's a solution to this problem?