Try taking them all out of the base dir, then start the game to make sure that is ok. Then add them back one at a time, starting the game each time until you find the one that is causing the problem. At least then you'll know what .pk3 file to look in.
If you have a lightsaber mod, it might be that. It's been a long time, but I think the menu files needed to be hacked in order to add custom lightsabers to the game. In any event doing the above would confirm that one way or the other.