I have several PS1 and PS2 cheat discs as well as other unlicensed discs.
A long time ago I remember trying to dump them all, and many gave me this kind of trouble. From the top of my head I remember the following:
Breaker Pro
HD Advance
USB eXtreme
Funny thing is: most of these problematic discs, I could just copy their contents and use them elsewhere, but never found a way to make a proper dump.
I don't have a Plextor drive, but will gladly try anyway to dump with various apps and get back with my findings.