The link on the register button is pointing at /index.php/component/users/?view=registration. It looks like it's getting redirected to the login page, so please check any SEF components you have enabled. You can also try turning off SEF in your Joomla Global Configuration area and see if that helps resolve it. This sounds like it is related to how your site is configured and not JFBConnect, since we're pointing at the correct link.
-Melissa
Register Button in modal popup taking to login page
