This is being caused by the mercenary scroll you double clicked. You do not have the right AI files to make those work and thus it errors you out. The all-in-one has the ai folder, though the ai folder is a tiny tiny thing. I could give you the ai files but with you not having the all-in-one installed the chance on other errors would remain big. So I would also recommend you to install our game through our all-in-one installer :).