The net result is that port forwarding works once again - keycount.piqsoftware.com is back live and pointing to the dummy placeholder page that got put up on my spare Windows server box after Milton blew up.
So tonight I think I'll put Milton up "live" and move the placeholder over (assuming I don't crash from this marathon I'm on, during which I've slept about 2 hours in the last 2 days). All I really need to do to get it finished is install PHP5 and MySQL, and that can be done with minimal disruption to the service of a static placeholder page.