MATSHITA DVD-R UJ-85J cannot burn TDK 16x DVD-R. Will not eject the DVD-R.

I haven't found an answer here, and nothing about firmware updates here either, so I thought I'd post a question.

Using the finder to burn some data to a TDK 16x 4.7GB DVD-R results in the burner emitting something like "failed to verify", and following that I cannot eject the disk normally. that is, the eject key does not work, "eject" is greyed out of the Disk Utility, etc.

Is there a fix for this? Or did I get a bad batch of DVD-Rs from TDK?

System Software Overview:

System Version: Mac OS X 10.6.4 (10F569)
Kernel Version: Darwin 10.4.0
Boot Volume: Macintosh HD
Boot Mode: Normal
...
Secure Virtual Memory: Enabled
64-bit Kernel and Extensions: No
Time since boot: 22:43


MATSHITA DVD-R UJ-85J:

Firmware Revision: FCQ5
Interconnect: ATAPI
Burn Support: Yes (Apple Shipping Drive)
Cache: 2048 KB
Reads DVD: Yes
CD-Write: -R, -RW
DVD-Write: -R, -RW, +R, +R DL, +RW
Write Strategies: CD-TAO, CD-SAO, DVD-DAO
Media: To show the available burn speeds, insert a disc and choose View > Refresh

Hardware Overview:

Model Name: iMac
Model Identifier: iMac5,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.16 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 3 GB
Bus Speed: 667 MHz
Boot ROM Version: IM51.0090.B09
SMC Version (system): 1.9f4
Serial Number (system): W86353NQVUV
Hardware UUID: 00000000-0000-1000-8000-0016CB9C6325