Steve,
our experience here is:
Be sure to have a volume label on every drive (seems to be ok regarding
your mail)
Set access to the root of each drive to (at least) "everyone show files".
When running the scheduler using the system account, "system fullcontrol"
works fine (this could be the point)
Be sure to NOT HAVE an audio cd in your cdrom drive. This caused older
ADSM ptfs to crash, I didn't check what happens today...

Good Luck!

Regards,
Michael