Thats not right, the metal maker AI is programmed to return a "must select metal maker" message, have you tried using other AI's? Maybe its the engine at fault here
I'm not sure WHAT caused it, but I've only crashed my game twice. This was one of the times, the other was because I put my whole games folder as "hidden" in windows. In other words the game couldn't access the files. Just seemed like it wasn't a coincidence.