well that is an odd problem.
1st - did he try the SAME media he used before to get a good burn? using the SAME software?
2nd - check for a bios update for the drive - manufacturer's website should have any if available.
3rd - is he finalizing the disc? sometimes the check bux gets un-ticked and I dont catch it for a while ( and that sux )
4th - dunno just wanted a 4th
Let me know, unless someone else answers ya first
Mike