illegal request:invalid field in cdb..

The error message says... The recording device reported the illegal request:invalid field in cdb.(0x24, 0x00.)

I'm trying to burn an hour and 50 minute iMovie to a Staples DVD-R disk. David Pogue's book says that if the assests aren't done to enable background encoding.. but that option isn't available in best quality mode. So I'm attempting to burn without that step completed.

I will try all the solutions I found so far - extra disk space, shortening the movie, using verbatim disks, burning a disk image first.

Is there anything else?

Thank you so much,

Greg