Thief 3 Technical problem

Hi all,

Ive just purchased thief 3 off of Steam, and the game plays fine until the third mission, when i steal the Holy Symbol/Cat o Nine Tails from Grietus. After this point, the game immediately crashes upon trying to save with the standard "has encountered a problem and needs to close error".

Anyone know a fix/way around this?

Steam would have downloaded it with that patch though would it not?

That patch also only fixes the known issue of resetting AI after loading a save, which has nothing to do with my problem unfortunately :(