I'd go with Massey on this one. He has a veritable wealth of information on these things, unlike that garrulous Jan Vigne who spends his time insulting rather than informing. I have never gone wrong taking Massey's advice.
Some of the Pioneer recorders use a standard PC type DVD burner that may be replacable. The recorder may or may not recognize the new burner though. Some manufacterers use some type of setup that only recognizes the burner that was initally installed. If you're interested in trying to replace the burner, look at Videohelp, there's been a lot of posts there about replacing burners and HDs in Pioneer recorders.
Reason for this: Beam is too close to center mirror index band It can happen from either DVD-R media or laser by burner is slightly too close. It can be ECC by substrat dye (concentring proplem)
Call Pioneer sometimes it is only $50 or $60 for replacement.