Can you specify a little bit? Are you using Windows, Mac or Linux? Have you mixed patches?
The most probable thing is that you messed up with the patch files, so check it again, or even reinstall it from the beggining if you want to be sure. Maybe there's another file you added that you shouldn't? And if its an error that appeared directly after adding the patch file, without doing anything else afterwards apart from booting up the game, something surely is wrong.