by Tony Galvão.
Hi dude, I had the same problem. In my case the problem was the theme ... I decided just commenting the lines of the custom menu;
$siteadmin = $topsettings->settings_tree($this-> page-> settingsnav);
risible_position_menus($siteadmin, $navigation, $hascustommenu, $custommenu, $home);
Sorry my english done by Google Translate. I hope help you.