Server did not return a valid Atom response

[Kattni <kittyfish kittyfish org>]

I'm trying to setup Drivel with Wordpress and my xmlrpc.php appears to 
be working fine when I go to it through a browser (it says blah blah 
accepts posts only, or some such thing.)  When I enter everything into 
Drivel it returns "server did not return a valid atom response".

Any ideas?

Thanks -- Kattni