I personally had a problem with levitation, slowfall, mark/recall, and Intervention spells working the steam version of the game. Whenever my character casted them nothing would happen. If you are having this issue it can be resolved by going into your steam "settings" then the "in-game" tab them make sure the box that says "enable steam community in-game" is checked off. Also make sure you open the game through your steam client. Not 100% guarantee this will solve your problem but it worked for me, so with any hope this will save someone else the frustration I endured.
