I was having an issue with adding my blog info to flickr, it wasn’t recognizing my login information. It requests 3 thing, the endpoint, your username and password. The endpoint address is usually something http://yoursite.com/xmlrpc.php, or if you installed the wordpress system into a different folder, such as blog or wordpress, then the end points would look something like this: http://yoursite.com/blog/xmlrpc.php or http://yoursite.com/wordpress/xmlrpc.php, respectively. The ultimate goal here is to provide the correct path to the xmlrpc.php file. I sifted through the help forum, which listed all kinds of responses, but the one that was key had to do with the settings in the writing panel in the WordPress Settings section.
About half way down there’s a check box that needs to be set, next to “XML-RPC: Enable the WordPress, Movable Type, MetaWeblog and Blogger XML-RPC publishing protocols.” It wasn’t checked, but once I checked, I was able to proceed through the process.