Unable to copy DVD Duplicator discs

[foolsfortune]

I have several DVD's that I'd like to back-up. The person that sent them to me says he copied them on a Kanguru 1-3 DVD duplicator.

I've tried DVD Shrink, Nero, Alcohol 120% and DVD Decrypter and am just about to try Clone DVD.

I get various error messages like:
Unrecoverable read error
Failed to read file D:\ no more data is on the tape
Invalid File structure

The discs surface looks perfect, they all play perfectly in all 4 of my players/DVD drives, I'm using the most current version of each software, and the firmware is current on my DVD recorder.

Any ideas? Surely these things can be copied. I could play them on my regular DVD player and record onto the dvd recorder, but I'd lose all the menus and chapters at the correct spots.

I appreciate the help.
Mike

[Baldrick]

test the dvds with nero cd-dvd speed to see if you can read the entire disc. your dvd reader may not like just that media.

you can also try extract the data with isobuster.