"Fixed the issue. Copied the files via 7Zip into a folder on the desktop and the installation worked for the non steam version."

To complicated for me. This should of course work by default. Slitherine, do you read this?

Thats exactly what happend to me... i got the "insert disc 2" text as well... Luckily i could activate the Steam solution and the problem went away. But you should be able to use the original install of course. Do it again, Slitherine and do it right.

Ok, i solved it. I simply registred for Steamversion and it worked fine. The regular install from Slitherine did not work though. Weird.

Why doesnt the installation works?

Have you really tested that?