function wpb_list_child_pages() {

global $post;

if ( 'movie' == get_post_type() && $post->post_parent )

$childpages = wp_list_pages( 'post_type=movie&sort_column=menu_order&title_li=&child_of=' . $post->post_parent . '&echo=0' );
else
$childpages = wp_list_pages( 'post_type=movie&sort_column=menu_order&title_li=&child_of=' . $post->ID . '&echo=0' );

if ( $childpages ) {

$string = '' . $childpages . '';
}

echo $string;

}

add_shortcode('wpb_childpages', 'wpb_list_child_pages');