PT 9.0.6 Crashes at startup - usual protocol not working
 

I really need help!
I can't launch PT (all versions 9.0 - 9.0.6) on my harpertown 8-core in 10.6.8.

I've tried throwing out preferences, I've tried deselecting everything from the PT Aggregate device. I have no 3rd party plugs on this system.

No matter what, I get a crash on startup EVERY time:

"Thread 34 crashed with x86 thread state"

I haven't used this system in while (but it hasn't changed since it was working). I'm not sure which audio driver was last used, but it shouldn't matter, cause I've re-installed and thrown out preferences multiple times.
Can anyone help?