I just updated WP to 3.1 and noticed an update to this plugin so I updated it as well. While the update to WP 3.1 was a snap, I can no longer get the CC plug-in to work. Each time I update the profile settings, it clears the username / password settings. I verified this by going into the DB. Even when I manually set the values (after they were cleared), the plug-in would not display using any of the settings I selected.
I am going to try to install an older version, but I hope this newer one can be fixed.