after repairing my permissions in disk utilities, it is mounting and playing commercial dvd's.
i had all the proper programs checked in systems preferences/cd-dvd prior to repairing permissions.
if my subject line offended your sensibilities, then i apologize. i will make a note of it for the future.
as always,
chung
ps. this computer is not my main computer so i don't i have repaired disk permissions in a long time which i do regularly on my tower.