I can't get to developer.apple.com either, via Safari, because to log in there, it goes through idmsa.apple.com , which again can't load the header.js and app.js and app.css resources.

The appleid trick is not working for me; I just get the same waiting icon.

Nice to know I'm not going nuts! Or: have some weird firewall blocking issue, although the fact that Chrome makes it through would count that out!

For no particular reason, it connected this morning and registered the device after a few plug-ins and out. So, there's hope for the rest of you! Thanks, Quinn!