It looks like this page is expecting URL parameters that aren't set. In order to avoid this error, just add a check to see if the variable is set when referring to it. So instead of:
php:
$WADAproducts->bindParam("i", "".($_GET['ProductCategoryID']) ."", "-1"); //ProductCategory
use:
php:
$WADAproducts->bindParam("i", "".(isset($_GET['ProductCategoryID'])?$_GET['ProductCategoryID']:"") ."", "-1"); //ProductCategory
and so on for the other lines referenced.
Did this help? Tips are appreciated...
