Thanks everyone for the ideas! :thumbsup:
I did a little more poking around on the CD and discovered that the Start_Here file was signed by a company called Hexalock, which provided copyright protection for CD files many years ago. They still have a website, but some say they're no longer a going concern. Either way, the heart of the problem is that the little executables run to deencrypt the PDF files before loading into Acrobat will not run under Vista or Windows 7. The website offers a fix for Vista, but my CD was way too old for that to work.
Googling, I found this thread:
http://club.myce.com/f80/hexalock-204559/
One of the thread participants (GoldStar611) pulled together a little VB6 program called UnHexaLock that masquerades as acrobat.exe so that the Hexalock happily deencrypts the requested file and passes it to UnHexaLock which then allows me to save the unencrypted file. Of course, I had to do this on a Windows XP laptop I still have access to; but now I can open these PDF files on my Windows 7 workstation. As an added bonus, I can also print pages (Hexalock would not let you save or print from Acrobat).
So, a happy ending. :biggrin:
I imagine that some may feel a bit uneasy over my circumvention of copyright protection, but I was pretty much forced into it by their failure to provide means for me to continue to access the material on the CD. I don't think it's reasonable for users who have purchased copyrighted material to lose access to it due to outdated software.
Thanks again for your help!