Plugin not integrating with NextGEN Download Gallery

Hi,
I am having trouble when using the Simple PayPal Shopping Cart together with the NextGEN Download Gallery. When I activate the PayPal plugin, my gallery disappears and a message saying “this is not a valid template” appears on the screen. The author of the NextGEN Download Gallery plugin has advised me that there is an error in a function within the code which diverts the template:

function wp_cart_ngg_template_handler($arg1,$arg2)
{
if($arg2==”gallery-wp-cart”){
$template_name = “gallery-wp-cart”;
$gallery_template = WP_CART_PATH. “/lib/$template_name.php”;
return $gallery_template;
}
return $arg2;
}

According to the author, the last line should be return $arg1; not return $arg2;
Thanks for any help or advice.

http://wordpress.org/plugins/wordpress-simple-paypal-shopping-cart/