Actually, I think I know what the problem is....
My first question is whether or not you have the "real" 4 disc version, or that weird 2-disc russian thingy.... I know that when I bought a copy of it off of ebay, I got a 2-disc version of the game in russian. When checking the files with a friends real copy, I discovered in the movie folder that all my movies were 1 kb. That's how they were able to fit the game onto 2 discs.