Presumably you can test it by disabling one of the 2 DVD drives and checking if the problem continues.
Make sure you have the 2 drives jumpered correctly. One must be master and one slave or (better) both on CSL (cable select).
Try changing the position of the drives on the cable.
Try putting one DVD as second device on primary IDE.
Anything in your PC bios that dislikes 2 x CD/DVD devices on secondary IDE? I had a Compaq years ago that just would not have it!
Assuming both DVD devices are "found" by XP, try uninstalling them both from the system and letting windows install the drivers again.
All I can think of at the moment.
SD