I didn't find any firewall actions - and yes, I've run into that as an issue with other games. Restarting, however, did apparently fix things... even though I'd restarted multiple times between installation and yesterday's attempt.
Ah well, now that it's working I won't question it. I dug out my old saves from a prior installation, and everything is now good to go!
Post edited May 26, 2011 by jurijchrul