I have tried Toast 7 data and VIDEO_TS burns for sizes around 6GB. They would fail fairly far out in the burn process with assorted "sense errors".
Finder "Burn Folder" work failed similarly with a more generic error message.
After tearing through $30-$40.00 of Verbatim discs this way I went to Staples and bought a 3-pack of Maxell to check another brand. A Finder "Burn Folder" burn locked up around 95% of the way through.
All of the above forced restarts with the power key: stopping, quitting and force-quitting didn't work.
Roxio and Apple mostly sent generic datasheets at me:
Thank you for contacting Roxio Technical Support
Issue: Sense Key\Code error
Resolution:
Please follow the steps outlined in this article.
After several phone calls to Apple I have convinced them that the machine has a bad drive. At this point I have to choose, having put many hours into loading fresh software onto this machine (I migrated very little from my G4) whether to do the 14-day-no-questions-asked return, take their offer of a swap for another machine, or take this one to a local service provider for a drive swap. I am over 2 hours from any Apple Store.