Training CD does not run (VOB Protect CD/DVD [modified version] )

As a medical student, I run training CD's in Parallels. Unfortunately one of them does not run, it says it "cannot find the original disk" when the original disk in in the disk drive. Older CD's from the same manufacturer run well. It seems a silly copy protection scheme is at work.
Both are from Urban & Fischer, now Elsevier.

The old one that runs, has
[!] Protect DiSC v6.2 - v6.8 (Build 13-09-2005) detected !
[!] exact version: Protect DiSC v6.5 !
[!] protection level: Basic

The new one that does not run, has
[!] VOB Protect CD/DVD [modified version] detected !

What can I do?
Thanks in advance