Ok, this still is a bit strange... but:
- I uninstalled NCS-32 and NCS-64, then I went through the whole registry and deleted EVERY key having the words "Moonware" or "Netcam" in it. After that, I deleted the respective folders in Program Files and in Program Data. (I even deleted my running webcamXP installation.)
However, there seems to be "something" stored in a hidden place (has maybe to do with your copy protection, whatsoever). As, after a new install, when I started the 64-bit client - it still had my server's IP stored
Anyway, the client now seems to work. Fine.
(Maybe I'll try later to switch my "webcamXP camera servers" to NCS, too, but for now I think I will port my "webcam server" only (one step after the other - makes it much easier to analyse things ).