So, here I am again! I ended finding out that what i was runing was a non-steam version of the game, although I only have that license, and wasn't achiving any achivements, but when i tried to run the steam version of the game happens what I said in the first post. So I am stiil in need of help!
Also: I could play a lot of the game in the "non-steam version" but the game that i saved doesn't appear in the steam version, and I would like to charge that saved game on the steam version, if there is a way, obviously xD.