I just started using Windows 8 and I'm having a little trouble getting used to it but I'll tell you how I got the trainer to work so you don't have to break your head over it.
I got the game on Steam so I just got the latest trainer for it. Caliber's doesn't work, sadly. So I got the #2 trainer and tried turning it on while in the main menu of the game and it crashed. What you need to do is actually go into the game and then press the menu thing and then activate the trainer and wait for the 2nd time it says "Activated". Then it works. Have fun!
You basically rediscovered the wheel.