Index: uc_node_checkout.module
===================================================================
--- uc_node_checkout.module	(revision 80)
+++ uc_node_checkout.module	(working copy)
@@ -348,6 +348,10 @@
           // Otherwise look in the $_GET array.
           $product_nid = $_GET['product_nid'];
         }
+        elseif (!empty($_GET['product_id'])) {
+          // For manually created orders the element is product_id
+          $product_nid = $_GET['product_id'];
+        }
         elseif (!empty($_POST['ucnc_product_nid'])) {
           // Try the $_POST array (for rebuilding a node via AHAH)
           $product_nid = $_POST['ucnc_product_nid'];