Thank you very much to my friend Mariano D'Agostino of Cuenco Digital (http: // cuencodigital.com/) for having said the errors to me in the code, this one is the new code fixed that Marian gave me (that works very well):
<?php
module_load_include('inc', 'menu', 'menu.admin');
$menu_custom = array(
'menu_name' =>'menucustomtest',
'title' =>'Menu Custom Test',
'description' =>'Esta es una prueba de crear menus custom desde linea de programacion'