Remove div from menu

Hi,
I have a personalized theme and use HTML5.
In validator, the div tag isn’t allowed with as a child of element ul and I try to remove this with the options and the PHP function and isn’t worked. I used regex to try this, but can’t work. The div appears on HTML, with the class option in blank.
Can someone help me?

<?php
$menu = wp_page_menu(array(
	'container' => '',
	'container_class' => false,
	'menu_class' => '',
	'sort_column' => 'menu_order',
	'exclude' => '5,9,23',
	'show_home' => 1
));
echo preg_replace( array( '#^<div[^>]*>#', '#</div>$#' ), '', $menu );

?>

Thanks,