new boy having a nightmare.....!

[Wayne]

Use Disc Juggler to copy the disc to an IMAGE, keep the settings at default (what Disc Juggler had when first installed).

Once you have a .CDI image file, you should be able to burn the .CDI back to another disc without any problem.

The point is, it's difficult if not near impossible to copy backups of Dreamcast games using a DISC-to-DISC method.

If you prefer Nero, you might try an experiment that worked for me when I was copying another type of disc that's sensitive to format...

Load REGEDIT (START / RUN / REGEDIT)
Go to: HKEY_LOCAL_MACHINE\SOFTWARE\ahead\Nero - Burning Rom\General
Look for "AddISOFileVersion" (should be at the top of the list).

Data contents will probably be a "1", change data to "0".

Apparently the version number appended to the file effects some programs (they don't like it). Turning this function off may fix Nero's inability to make good backup copies. I just don't know for a fact.