Years late but who cares for people having problems further on the line closer to my date i also using trial and error found another way
- first move any wanted things out of mount and blade folders such as mods ect
- Unistall mount and blade through steam
- this will leave two folders (Mountblade warband) and (mount&blade warband)
- I deleted both of these folders
- re-install mount and blade through steam
- this should take longer as its basically re-installing the game from scratch which should fix the error you cant find.