Hi @MaulTCat. Welcome to the Community
I have experienced this problem myself. But mine was through Uplay itself and it was trying to play a Uplay+ Version of the game.
Have you Loaded the game first and then started Wemod? Sometimes it works one way and not the other.
If this Still fails, You can find the Games .EXE and tell Wemod to load directly with that.
(Using the power of my mind to merge this post with the Thread!)