Fatal error: Call to a member function add_current_page() - around line 312 or

[admin]

Somehow seems the navigation parameter remains registered so the class is not instantiated. Do this to fix it.

Fatal error: Call to a member function add_current_page() on a non-object in /includes/application_top.php on line 312

1. Backup catalog\includes\application_top.php then open it locate this code:
CODE
// navigation history
  if (tep_session_is_registered('navigation')) {
    if (PHP_VERSION < 4) {
      $broken_navigation = $navigation;
      $navigation = new navigationHistory;
      $navigation->unserialize($broken_navigation);
    }
  } else {
    tep_session_register('navigation');
    $navigation = new navigationHistory;
  }
  $navigation->add_current_page();


Replace it with this
CODE
// navigation history
  if (tep_session_is_registered('navigation')) {
    if (PHP_VERSION < 4) {
      $broken_navigation = $navigation;
      $navigation = new navigationHistory;
      $navigation->unserialize($broken_navigation);
    } else {
      $navigation = new navigationHistory;
    }
  } else {
    tep_session_register('navigation');
    $navigation = new navigationHistory;
  }
  $navigation->add_current_page();