eCart & DFP downloads: db updated, but download not working

In the session dump, the session that is created is UserID:
["UserID"]=>
string(1) "4"


<!-- Dump session for trouble shooting purposes -->
<pre>array(8) {
["UserID"]=>
string(1) "4"
["eCart3_Items"]=>
string(242) "1|WAECART|Basic libretto/script |WAECART|Complete, unadorned version with full references to backing tracks and guide tracks (Word document)|WAECART|0|WAECART|1|WAECART|0.01|WAECART||WAECART|0|WAECART|0.01|WAECART|1 Basic libretto/script (1)"
["WAEC_ContinueRedirect"]=>
string(20) "/resources/index.php"
["eCartCheckoutForm_state_province"]=>
string(0) ""
["eCartCheckoutForm_country"]=>
string(2) "GB"
["eCartCheckoutForm_shipping_state_province"]=>
string(0) ""
["eCartCheckoutForm_shipping_country"]=>
string(0) ""
["eCart3_OrderID"]=>
int(34)
}
</pre>




In the WAOrdrs recordset, you are filtering on a session named OrderUserID instead of UserID

$WADAOrderUserID_WADAorders = "-1";
if (isset($_SESSION['OrderUserID'])) {
$WADAOrderUserID_WADAorders = (get_magic_quotes_gpc()) ? $_SESSION['OrderUserID'] : addslashes($_SESSION['OrderUserID']);
}