You wont find much help here, but you will if you head on over to
tech support and post this thread there. Those guys can fix most of your problems!
But a quick fix (I'm not sure if it would work) would just to create a bogus file named after the sprite it cant find. That should just wave the check for the sprite, but when it needs the sprite your up the creek without a paddle. If all else fails, try to reinstall NS!
Hope it works!!