you must have had a faulty duplication then.

My master was obviously fine, and I was sent samples from the first batch of duplication which I signed off as fine.

Also was asked to demo some random ones from the racks at a couple of dealers and those worked ok, and a few others have discussed the contents here so theirs worked too, so maybe there is a batch problem.

Undoubtedly Technote will sort you out.

Incidentally I mastered the cd as cd-extra, the latest format, which has advantages over the older mixed-mode format in that audio cd players cannot see the data at all.

Otherwise if I made a mixed-mode cd very old cd players can try to play the data with unfortunate results if you have the loudspeakers turned up high!

There are other advantages of cd-extra in the organisation of the tutorials and making those step by step instructions using the cd easy to follow in the book.
A by-product of this newer format is that it is more difficult for auto-duplicators than standard audio or data cds.