Are you using version 1.134? Or the latest warband?
If you are using the latest warband you need to download 1.134 instead, as this mod hasn't been updated for the latest warband. You can always do this by going to taleworlds server download page, copying the link, going to a text editor or word processor, pasting it, and then adding 1134 to the end rather than the current version number. Then copying it again, and pasting it in your browser window.