On the FECC message board several (UK and Australian) fans complained that the second disk from the Comeback DVD set has problems. Some DVD players did not recognize the disk, on others the image freezes or the disk "jumps" at several places (e.g. "Trouble/Guitar Man" all takes section).
The second error is is a lesser problem. The second disk of the Australian edition of the "68 Comeback Special" DVD set is labeled as "disk 1" in stead of "disk 2". Perhaps a future collectors item.