hook_menu and Access Denied
For the first menu item, you didn't provide any page callback, and MENU_DEFAULT_LOCAL_TASK menu items inherited it from the parent menu item. In this case, Drupal returns a 403 error.
For the last one, the reason can be one of the following:


The page callback function doesn't exist, or it is defined in a file that is not the module file
The user account doesn't have the permission 'access content'