I finally pinned it down to one thing. It seems every trainer that does not require you to press F1 to activate it doesn't work for me.
I'm having the same issue. I have a windows 7 ultimate x64 and I couldn't seem to find a solution to make the trainer work outside using my dual boot and going back to vista. I'm hoping they will update the trainer when and if they do another update for this game.
download the trainer again and dont forget to use the shift key.
it will work. be sure about it!!!