One of the first things you need to do after you install CB for the first time is to configure a Joomla menu for your CB User Profiles.
This is a mandatory step required by Joomla.
Select 'Add New Menu Item' from your Joomla: Menus :: (select the menu you want to use) area and choose the Community Builder :: User Profile (mandatory) menu item type from the Menu Item Type popup window.
This Joomla menu must be published for Public viewing since it will be accessed by the CB registration process and thus needs to be publicly accessible.
You can place this menu item in a Joomla User menu that is published for registered users. This way you will avoid actually showing guest website users your CB Profile menu link.