Do you have CUDA enabled? If so, try disabling (go to sofrtware only) and see if the problem still happens. It seems there are lots of CUDA issues on the Mac that still need to be resolved. we have CUDA disabled most of the time and only really enable it for final output rendering. Sad, but true.
Ah, I didn't think of that. Yes, I had the GPU accerlation enabled. A while back, when I was on 10.7 Lion, I had a particular project that sporadically crashing Premiere with the "Premiere encountered a serious error..." message. I had read on here somewhere to try turning of GPU accerlation. After I was done with that project, I re-enabled it and hadn't had a single problem until yesterday. Maybe OS X 10.8 didn't fix much?
I can make my Mac (no cuda) crash by keyframing position on a 2500x1000 px .jpg and then turning off the position stopwatch.
PrP warns me that the keyframes will be deleted. when I accept, it crashes. This also "works" when I turn off the stopwatch on time-remapping.
yikes. Any thoughts?