imation DVD-R 8x not being recognised

Hi,

I've inserted a number of blank imation DVD-R 8x discs into my iMac G5 (PPC) (purchased almost 1 year ago) and the the machine churns for a little and then ejects the disc. I've tried different batches. No luck. DVD+R 8x work fine as does CD-R.

System Profiler info:

MATSHITA DVD-R UJ-845:

Firmware Revision: DBN9
Interconnect: ATAPI
Burn Support: Yes (Apple Shipped/Supported)
Cache: 2048 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, DVD-DAO
Media: No


Would appreciate advice on whether these discs should be supported.

Regards, Tony.