I’m having the same problems. Running CS3 with nothing in the background. Audio randomly drops out while playing back clips on the timeline.
For me, I’ve noticed it has only been happening with a Sony EDCAM EX project (I’ve edited DVCPRO HD projects without this problem).
I’m running a pretty beefy machine, plenty of system resources.
I haven’t been able to find an answer to this problem anywhere on the web though?