Have you tried to change the DVD port? I looked through the DVD forums and
newsgroups and your question has arisen in virtually all of them, but usually
without any useful replies. One person who originally reported your problem
later answered himself as follows: "I actually had a bit more of a play and now
have found that the DVD works in any config as long as its on IDE1, secondary."
Swapping ports didn't work for the following guy who found a different solution:
"I had the same error.. tried everything, swapping IDE channels, the works... nothing.
I finally figured that the copy protection was being turned on by software, and this
was preventing the drive from playing. That's when I realised I had been imaging
some CD's and Nero was left with the hard drive image as the active recorder. Opened
Nero,switched the burner from the image creator to my burner, and my DVD's work again!"
Interested to know if this is a case of CSS run amok or just something weird.