Are you having problems connecting Flickr to your Wordpress blog? Are you getting errors that your username and password settings are incorrect when trying to set up your API endpoint?
Here is the solution: in the Wordpress Settings section, select the “Writing” page. Check the box next to “XML-RPC: Enable the WordPress, Movable Type, MetaWeblog and Blogger XML-RPC publishing protocols” and save your settings.
Then go back to your Flickr blogs page and add your blog again - and that should do it!