I’ve been having the same problem.
CS6.02. Brand new Mac Pro 12-core with 64GB RAM, Kona LHe plus, Quadro 4000. Boris BCC and a few other assorted plugins.
Crashes randomly with the “Sorry a serious error has occurred” message. Yesterday I spent some time on the phone with Adobe support to address the problem.
The support guy had me create a root user on the Mac, and operate Premiere under that user as a temporary trouble-shooting procedure. Suddenly, Premiere is working faster, has far better real-time CUDA playback performance and is crash-free. Unfortunately, the Kona card is not recognized. But then, maybe that’s what’s causing my problems?
I’ve just started using Premiere after years of Avid DS and Final Cut 7. I really like lots of things about Premiere, but if we can’t get all the parts to work properly together, I’ll have to move on from Premiere.