Thanks Rüdiger and Roddy,
I have W7 Enterprise and tested with installing the XP version. I got a message the Microsoft.NET Framework 1.1.4322 was needed. I installed it and then son2xtf. Son2xtf works well.
However, SiView doesn't perform well. Some recordings, also old recordings, become 'diagonalized'. I have never seen this before. It's strange that some recordings look normal, some not.
Fortunately, Humviewer installed without problems and show the recordings which were diagonalized in SiView without any distortions.
Rickard
ADDED: I just discovered the 1.0.0.6 patch for SiView 1.0.0.5. No more diagonalized images, problem solved!!