The link that the Register buttons are pointing to look correct at /index.php/component/users/?view=registration but when you click it's redirected to view=login. Please ensure that registration is actually enabled on your site. In the Joomla User Manager, this is the "Allow User Registration" setting in the Options. If it is already enabled, I would then suggest trying the standard Login module and see if its Register button works properly as well. Let us know how this behaves.
-Melissa