Mystery solved, and thanks to everyone who helped.

I tried five CD writers, thinking this was the problem. But in all cases I
used ISO Recorder:
http://isorecorder.alexfeinman.com/isorecorder.htm

Iso Recorder created CDS that booted Linux fine, on PCS and even on an
Alpha-based Multia.   They cannot however boot a VAX.
When I used my husband's copy of Nero, the CDS booted fine on several vaxes.

People might ask why I didn't record CDS on another Unix machine; that's
because one is temporarily down and the other was not available.

Now that NetBSD is installed on my play VAX I get to play with package
dependencies. Again, thanks to everyone.

--Debee