I just came down with this problem today after using this burner flawlessly for several months. I was using Sony DVD+RW, Nero 6.603 Ultra and InCD 4.305. I used this media for backup. Anyway Quicken tried to access the drive for a backup and couldn't packet write to the DVD. "Access Denied" is the error message. The existing files on the DVD+RW are Read-Only, and if you go to the Property Sheet there is no more Free Disk space.
I upgraded the software to the latest versions of Nero and InCD, uninstalled and reinstalled the burner in the Device Manager. Device Manager says the drive is working properly. Nero Info Tool says the burner has all the write characteristics. It will Packet Write to a CD-RW but not to a DVD+RW. It also burns to a DVD-R, and plays DVD's. Please HELP!