I am trying to back up iTunes movie files (.m4v) to a DVD+R-DL disk (Sony brand). I am not trying to break any copy protection - I just want to back them up as data files so I can archive them and make some more space on my hard drive. Every time I try to burn i get an "illegal sense error", I have made 4 coasters already. I tried Toast 10.0.6 and 10.0.8. I am running Mac OS X 10.6.4 on a 15" Macbook Pro, 4 GB RAM, 500 GB hard drive.
The Macbook Pro is up to date with all of the latest software and firmware upgrades.