Just a thought here... I once had the same problem. It was because Nero 6 was saving the file as it was being transferred to a temporary file on the hard drive (or was using the OS to copy the file), and trying to burn the CD at the same time. Sometimes it would report a successful burn, but screw it up anyway. The problem occured because the hard drive and the CD burner were both on the same IDE channel. The IDE interface cannot perform both read and write operations simultaneously. Once I moved the burner to my secondary IDE, it worked fine. It could be that the transfer and burning is occurring too slowly to cause a buffer underrun, but is screwing the data up when it passes through your IDE interface and it is not being detected by Nero. Have you tried copying the files first? If it burns after a copy is made, then try switching the burner to another IDE channel.