Go to System Profiler and see what Disc Burning shows. Do you have an MDD?
Disc Burning shows for me:
PIONEER DVD-RW DVR-110D:
Firmware Revision: 1.39
Interconnect: ATAPI
Burn Support: Yes (Apple Shipped/Supported)
Cache: 2000 KB
Reads DVD: Yes
CD-Write: -R, -RW
DVD-Write: -R, -RW, +R, +RW, +R DL
Burn Underrun Protection CD: Yes
Burn Underrun Protection DVD: Yes
Write Strategies: CD-TAO, CD-SAO, CD-Raw, DVD-DAO
Media: No
The drive is set to Cable Select? Cables and Power connection firm?
Regards,