Yep I'm playing the retail version as I'm in the UK and got the game early, and the trainer is definitely causing the game to crash. I would say it's probably GFWL that's causing it. Would sending you guys the .exe be of any help?
I don't think it's GFWL, as I've tried disabling it and the game still crashes when using the original exe so it's probably the exe itself. I think I'm going to wait until they update the trainer to work with the original exe since any progress gained while playing with the crack can't be transitioned over to the original game (well at least not without hex editing the save file)