PS- We have not seen a reason to believe that the trainer is no longer working. The error you are reporting is typically associated with not activating the trainer at the precise moment (or the other steps need to be re-done).
I'm not trying to get the trainer to work again. Basically I was using the trainer, all was going fine. I friend joined me. I instantly quick the game, and tried to load the game up without the trainer so I could play with said friend legitly. And now I can't load the game at all. I'm assuming him joining me while I was playing messed up soemthing. I went through all the steps I did the first time to get the trainer to work, but no matter what I do the game (without using the trainer) will not load. without getting the error I mentioned before.
Yeh, it could simply be a case of a corrupted game or GameGuard file.
Incase anybody else gets this issue. simply verifying the system files on steam and then redoing the steps mentioned in the trainer seems to have fixed the issue.