Index: uc_product.module
===================================================================
--- uc_product.module	(revision 6)
+++ uc_product.module	(working copy)
@@ -404,7 +404,7 @@
     $products = db_query("SELECT DISTINCT nid, type FROM {node} WHERE nid = %d", $saved_args[1]->nid);
 
     while ($product = db_fetch_object($products)) {
-      if (in_array($product->type, array_keys(uc_product_node_info()))) {
+      if (in_array($product->type, module_invoke_all('product_types'))) {
         $forms['uc_product_add_to_cart_form_'. $product->nid] = array('callback' => 'uc_product_add_to_cart_form');
         $forms['uc_catalog_buy_it_now_form_'. $product->nid] = array('callback' => 'uc_catalog_buy_it_now_form');
       }