I ran a short test this morning with only 2 fixable problems. The first problem was Novation Automap 3 (which gave problems with other audio software as well). That generates some aditional plug-ins which are identified with the (automap) extension. I took that off and deleted the additional plug-ins it had generated.
The second problem occurred when I exited ProTools and closed VE at the same time. That caused PT8 to hang. (I won't do that next time).
I have PT8 LE with the latest update- latest VSL and latest OS X (10.5.6 which is not yet qualified for PT8). I have the 3.2 MacPro which has 8 cores, 10 gigs of RAM and 4 hard drives with tasks distributed between them as recommended by VSL.
Although my testing was not exhaustive I was running a 3D animation render in the background to which I had assigned all 8 processors- and there were no noticeable artefacts. VE sounded normal.
I don't have any useful suggestions to make other than erasing the system drive and doing a complete re-install (remembering to back-up and data on your system drive) which I do here every six months or so and it often fixes problems.