I am using a Mac and having the same problem. At first I thought it was a new hair causing the problem, so I got rid of the last hair .package I had downloaded and was still having the issue. Then I tried deleting awesome config which I had added recently and suddenly all my custom hair worked again. But when I tried to re-install the hair I had taken out, all my hair was borked again, and now it won't work no matter what.

I am patched and have the latest awesomemod. I don't know that it's my graphics card, since custom hair was working perfectly before and I think I have a decent card (GeForce 8600M GT).

oh, it might be worth mentioning that the only hair I had downloaded from TSR (in a sims3pack file) still works fine. But it is fugly and provides no consolation.