I am having a similar problem.... I have a brand new DW1620.. witch I found out is a bulk version, since it doesn't state "BenQ" on the tray.
The drive has problems on reading files from cd's... usually executable files, but not limited to this type... it often prompts me with CRC errors. But it's not a problem with the media, since it doesn't happen in other drives and also affects new media (audio cd's, recently purchased games, etc). It also doesn't burn dvd's under windows (I was able to burn one dvd under linux... but not all linux distributions work: I tryed to install slackware and it couldn't even read the installation cds....)
I tryed to fix the problems by upgrading the firmware. I then noticed that the firmware version was B7U9, witch is a firmware for the retail version (right?). Is that a problem??? Shouldn't the firmware version start with G??? If it doesn't matter if you use the G... or B... firmware, why are there two diferent versions in first place???
Anyway... the program that upgrades the firmware didn't let me transfer the G7V9, so I upgraded to B7V9... And nothing changed at all....
I don't know what causes this problem and what I should do to fix it... Should I downgrade the firmware? To witch version? How to install a G-firmware once the drive is already B-upgraded?
Or is it a compatibility issue? My motherboard is PCchips M863G, mobile Athlon xp 2400+, 512Mbytes RAM. The hard drive works fine (as pri-master.... dw1620 is sec-master)