Just a response to let you know that Tafferpatcher did in fact work for thief 2. A definite reccomendation to anyone also experiencing this glitch!!

Yet I'm having another problem with thief 1. The patch doesn't seem to think that thief 1 is installed, no matter how many times I re-installed it through steam, and backed up the files in another foulder. Sorry to bother you again, but despite the patch working, the game isn't installed properly, I guess.