516846 Joomla Jomsocial Registration Error

We have JomSocial pro component installed on a rockettheme website at http://www.womeninmusicandart.com. The registration process here [login to view URL] does not complete and goes to the following error page: [login to view URL] You don't have permission to access /[login to view URL] on this server. Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request. I need someone that knows JomSocial that can make this work quickly.