Sims 3 Supernatural expansion pack for PC/MAC issues. Downloaded from Origin.

Here's a few trouble shooting steps: http://answers.ea.com/t5/The-Sims-3/Links-to-Mac-help-threads-and-guides/m-p/749664#U749664

If those don't help, I would suggest posting in the mac forum at thesims3.com (make sure your language is set to US): http://forum.thesims3.com/jforum/forums/show/205.page since macs are not well covered on the AnswerHQ.