"I burn all my backups onto Verbatum DVD+R"
That is the best xbox drive, people love it because it can read cd-r's without a problem and they almost never die. They are built to last. You could probably sell it on ebay for $80 at least.
However, with all their greatness, they simply do not read dvd+r's. Some people claim that theirs reads dvd+r's, but it must be a rare occurance. Anyways, you will have to change your media
. dvd+rw's may work, but you might want to buy a single disk in case it does not.