Hi Pero,
I took a look into the ASN.cfg file and figured that there where date given in MM/DD/YYYY format.
After changing my Windows 8.1 from German to English US the dates on my machine were displayed as DD/MM/YYYY.
I have just switched the date format on my machine to DD.MM.YYYY and now SimStarter opens the ASN config page without any problem.
So it was a confusion of the date format in the cfg.
From my point the problem is solved and the case is closed.
Vielen Dank für Deine schnelle Antwort und den entscheidenen Tipp :-)
Viele Grüße, Tom.