Never have seen this error before, Digi, anyone, please help!

[Mt.Everest]

Every 2o min or so i get an error (-6027, i think) that says, "Cant play back because too many virtual tracks switching" or somthing to that effect. Regardless of session size-- 3 tracks or 30. Then when i try to engage play from anywhere in the session, the same error pops up and refuses playback. If i try to quit, PT just does the "unexpectedly quit thing".
Now heres the freaky part. After PT shuts down on me, DAE is left still open. Yet The DAE icon in the upper right apple menu that lists what apps are open is all messed up. Like its just a bunch of dots and lines, not the familiar gray and blue lil' icon.
Then when i go to the actual DAE app in the system folder, the preferred,sugessted, and minimum memory settings are all at 384K and cant be changed.

So then i restart and try to load PT and I get error -199 on loading and thats it. I look at the DAE app and still with the 384k thing. Sometimes, it will be back to normal and PT will load but rarely. And when it does the error happens in 20 min again anway. I usually have to reinstall DAE each time. This happens every 20 min or so even after i tried:

Reinstalling PT in full multiple times
trash prefs, digi setup, mac os prefs, finder prefs, or any pref possible related
rebuild desktop
run norton utilities with no errors found
zap pram
reboot hardware
run MAC OS base extension set with digi stuff enables

Any ideas? heres what i have:
PT 5.1 mix plus with USD
G4 500, 256MB RAM (allocate 64MB to both PT and DAE)
Exp Chassis (digi approved)
Atto dual card, glyph 18gig 10000 cheetah drive
OS 9.1
Basically as standard as you can get. A textbook PT setup run by myself, an experienced MAC and PT user... The sessions i run are usually small, like 10 tracks, nothing fancy

please help.. i think ive tried everything expcept a different mac OS, upgrading to 5.1.1, adding more ram (I know 256 MB is kinda low) and obviously reformatting the mac drive and starting from scratch which i dont want to do if i can help it...

HELP
MT