admin menu page displays 'Cannot load cms/products_admin.php'

Hi guys,

I have added a admin menu page called ‘Products’. This shows correctly at bottom of the menu structure.

When I click on the ‘Products’ menu page it displays
‘Cannot load cms/products_admin.php’

products_admin.php is stored under
wp-content/themes/mytheme/cms/products_admin.php

Code is executed in functions.php file under:
wp-content/themes/mytheme/functions.php

add_action('admin_menu', 'shaneetsingh_cmsForWebsite');

function shaneetsingh_cmsForWebsite(){
	add_menu_page('Products', 'Products', 'administrator', 'cms/products_admin.php', '', '', 81);
}

In products_admin.php I have:

<?php
echo "hello World!";
?>

Can someone please help me to solve this problem?

Thanks