Well, as I said it's propably related to WMI, which I'm using to retrieve the OS string under windows. It's possible that the needed WMI object is not defined under your os'es.

So I've compiled an exe without the WMI-capturing of the OS name (just commented out), please try and tell me if it works : http://www.saschawillems.de/misc/glcapsviewer_nowmi.exe

If it works for you two I'll see how I can get around this, as I'd like to include the OS string in order to differentiate same driver versions on same GPUs for different OSes and need the OS name for that.