[BodyBalance]

This directed me to cart.php and posted the following on a blank page:

array(3) { ["mode"]=> string(12) "add_multiple" ["productid"]=> string(0) "" ["amount"]=> array(5) { [1]=> string(1) "4" [5]=> string(1) "0" [4]=> string(1) "0" [3]=> string(1) "0" [2]=> string(1) "0" } }