F.E.A.R. 3 - unable to initialize game - unknown error

[Companion Cube]

I just can't play this game, it just don't start. Everytime i try to execute, just a few seconds after the window "preparing to initialize game" i got this error message: "unable to initialize game - unknown error".
I'v tried everything people told me to do and nothing works. Someone can help? Or maybe steam could help me and fix this bug so i can play the game or give a solution to this problem...