I have the exact same error message -- "Optimal L1 Data Zone Start LBA: None Found! (VTS_03)" -- and the same problem as the OP (I don't have the disk anymore).
I have the ISO file and the MDS files from ImgBurn, but I don't have any files or folders to use "build" in ImgBurn.
Is there a way to fix this issue without the original disk and without any other files than the MDS and the ISO file? I have made backups of disks many times with ImgBurn and never had a problem before, so I was mystified when this happened.