ARccOS is a DVD copy protection mechanism which distributes bad sectors across the disc.
Can be trivially circumvented with dd_rescue:
dd_rescue -A -B 2048 -v /dev/dvd DVDBACKUP.iso
This backs up the DVD in /dev/dvd to the file DVDBACKUP.iso
-A tells dd_rescue to zero-fill bad sectors
-B 2048 tells dd_rescue to skip forward a minimum of 2k when it encounters a bad sector
ddrescue -n -b 2048 /dev/dvd DVDBACKUP.iso
2k is the DVD sector size.
Added: You may need to open the DVD initially with decss. Just start "mplayer dvd://1" then quit and run dd_rescue.
Note: GNU ddrescue supercedes dd_rescue. See http://firstname.lastname@example.org/msg00038.html