That's weird about the clay head thing. You didn't accidentally "Set as Head" did you? Anyway, thanks for the cheat. I'll give it a try when the opportunity arises. For those who aren't getting the "Investigate Object" option, you aren't Shift-Clicking, are you? It's added to the basic object menu. Just buy a Lump of Clay from Buy/Build (Kids Toys sort), set it on any viable surface and click it. You should get 3 options. "Put in Inventory", "Mold Clay" and "Investigate Object". If you choose the latter, the Sim will approach the Clay, spin around in a swirl of sparkles and they will have magical powers.
If you do all that and the mod is correctly installed but it still doesn't work, it's likely there's a code conflict with one of your other mods. Sometimes you can get more than one mod that modifies or overwrites the same lines of code in the game and they will interfere with each other.