[Current Issue] Sims 3 "serious error" when loading save

Is this an existing save or a new one?  If it's an existing save, please try to start a new one in Moonlight Falls and see whether it loads.  The question is, can you load the world at all, and only the save is broken; or is the world itself broken?

Please also let me know whether any other saves are affected.  If you don't have any, start one (no need to spend much time on it; this is just for testing), save, quit, restart your computer, and try again to load it.