OK, I solved it myself, the only problem is that I needed a lower user_level. It works with 2:
<?php
define('__DIR__',pathinfo(__FILE__,PATHINFO_DIRNAME));
add_action('admin_menu','menu_panels');
function menu_panels(){
add_menu_page(__('Panels'), __('Panels'), 2, __DIR__ . '/pag-panels.php');
}
?>