It's a new CD from MercedesManuals.com. It's called the "1956-1972 Mercedes-Benz Star Classic Service Manual Vol 4" and is a 2 CD set. It has the same splash screens that bpossel posted earlier in this thread, so I believe it to be the real thing content-wise, but it's possible that it's 5-guys and a printing press reproducing them.
That said, it works fine if I run it under Windows XP, but still using FireFox. This leads me to conclude that the media is fine and the files are being read without issue, but that there is a software problem somewhere, most likely in the ShockWave code on the CD. My first suspicion would be that it's making some compatibility check that was a good idea 10 years ago, but it causing a problem now.
Interestingly, the workshop manuals for the 190 and 300 which are on Disk 1 work fine on the Mac.
I seem to be a magnet for problems like this.
I'd be real interested to connect with anyone using these CDs on a Mac so we can compare notes.
Thanks