That's interesting, I'm trying to think whether I have tried using my normal desktop (as opposed to the core). I'm sure I would have tried that, but I can't specifically remember, will try tonight to be certain. Maybe it only worked because your cameras are connected to your router as opposed to the core?!
Anyway, I tried doing it through my VBox XP installation last night, and whilst I am feeling dirty all over, I had some success. Both the Foscam utility and web admin (in IE) were able to set static IPs (no more nasty errors on the web page). The IP Addr and Subnet Mask were automatically filled out correctly, but both Gateway and DNS Server were filled out with the same thing, 192.168.80.1. Obviously this isn't in line with the network settings in web admin, so I will change this tonight and see how it goes.
Yes, I am using wired.