Dr. C,
Glad to hear you're willing to give it a try. Let us know how it goes.
Here's the thread with details about the latest NR beta:
http://promixis.com/phpBB2/viewtopic.php?t=14483&sid=54e2bbd1d994311fc7e23462ab6256beSorry to hear you're having issues with NR on your Ax. I've got an X51v also and NR seems quite solid running on it, both in the cradle and via WiFi. I haven't done much with IR other than trying to translate the CCF from my old Pronto remote. That didn't work too well - many of the IR codes didn't seem to work.
If you're trying to out on the web with the UPnP server, you're beyond my personal experience. From what I seem to remember from roaming the web is that it's not likely to work. I think the J River gurus could give you a more authoritative answer.
As for using UPnP in your own LAN I only know of one solution that works. There's a free UPnP control point that works with the Roku players only - both Win32 and PPC versions are available:
http://www.tl-it.de/media/pages/visualmr.phpThere's another control point for the PPC avalable from Rudeo, but it doesn't work with MC's UPnP server.
Good luck...