Help with RPC?

I’m trying out the beta version of NetNewsWire Pro, specifically it’s Post to Weblog feature (cool idea). It seems to want a password, though, to post to this blog, and I don’t recall there being a password here, at least not one I’ve had to enter since I first set things up.
It also gives a 404 error when it tries to post, which makes me think that it’s guess for the RPC address to hit is the source of the problem. Has anyone set up a remote client like this before who can fill me in on the details needed?
NNW Pro guessed http://radiofreeblogistan.com/RPC2 for the RPC URL and “home” for the Blog ID, both of which smell fishy to me. Any suggestions?