If you are like me, any response that does not help or you have already tried, will just make you mad as hell. So I sincerely apologize, if any of this fails you or you have already attempted.
This sounds like a incomplete or corrupted download or a problem with the primary Mount & Blade program. Can you run any other mods? I would attempt to re-install both which you have already probably done. For the Steam version I know a few weeks ago they were doing house cleaning on the Steam Side and sent out a series of 3 bad updates, so this may have afflicted you. I am sorry if none of this helps, but we want to get you up and running! If you have any more info or error messages please let us know, additionally join the discord server and someone may be able to walk you through potential fixes, most of the people in there are nice.