Can't Login or Register

when trying to register an error of Empty solution not allowed. presents itself and the registration cannot be completed

This sounds like you have some sort of Captcha solution on your site, or something similar, that's likely preventing the registration. Can you check if you've enabled any plugins that try to perform a captcha/human validation on the user? If so, I'd try disabling it. JFBConnect has been tested with the default Joomla captcha, but 3rd party extensions have caused conflicts in the past if they aren't coded properly.

when attempting to login - it is unsuccessful and a message of You can not access private section of the site presents but the visitor is never logged in to access anything.

Is this when logging in with JFBConnect or with any Joomla user credentials? The only time I've heard of this happening is on sites that were upgraded from Joomla 1.5 and the upgrade was not done properly. In that case, the user groups table can be corrupt or incomplete, and so the authorization checks can't be performed. You may need to try and create a new User Group and Access Level for 'Registered' and assign users to those groups.

Let me know if that helps. Above all, let me know if the problems are just with JFBConnect or with standard Joomla registration/logins as well, as that will help narrow things down.

Thanks,
Alex