I'm trying to back up files from my Mirrored Drive Door Power Mac G4 with a 2x SuperDrive. I keep getting verification errors after burning a DVD-R. I have tried both Apple-branded and Memorex-branded DVD-Rs; both gave me verification errors. With the Apple media, the disk structure was lost, making the DVD useless. With the Memorex media, Disk Utility was able to mount the DVD despite errors that its Verify function detected, but it takes many minutes to display the contents of a folder on the DVD and I get errors trying to open individual files (e.g., "unrecognized file format" when trying to open a jpeg among the files I copied). Therefore, neither of my backups is useable. What is the most likely cause? Very bad luck by having two bad DVDs by separate manufacturers? A bad Superdrive? Writing at 2x is too fast?