It is interesting that some disks won't work on your Powerbook, I have a 3-month old Powerbook G4 that refuses to read or write on Maxell DVD-R printable disks. These disks work fine on my Powermac G4, on my Windows computer and on my 2 DVD players. I took some of these Maxell disks to the Apple Store and learned they would not work on any of the Powerbooks with the newer dual sided DVD disks. This is probably related to the same issue as the Reunion disks that would not work for you. I have found in the past that the Reunion tech people are about as good and as cooperative as any I have ever dealt with. Glad they fixed the problem for you with different disks.