I had been RDP'd into the actual server, and was using the NCM program to try to remove the node itself. On the server, it opens up an internet explorer browser pointed to itself, probably to the same page you're referencing.
If I go to that address via https on my desktop and using our server's ip, it does bring up the NCM add/remove page. Trying to remove the node in question from that page gives me a "Selected nodes already removed from NCM." but it clearly isn't when I check the actual server. I'm not sure what to do at this point except recommend a software upgrade or rebuild.