<So the problem was a Parallel port Dongle?>

Yes, I've forgotten over the years that there is something additional behind the old PC, Dongle is the right expression.
For the developer of the software it would probably only have been 1 second to think about it, to draw my attention to it.
But that's the way of security to lose customers.
The opposite is Michael and many of these forum users, I'm glad this is so.

Thanks for the tip, I'll follow every lead from now on.

Have a nice day
Franz