diff --git a/uc_attribute/uc_attribute.module b/uc_attribute/uc_attribute.module
index fd63d64..c5e6353 100644
--- a/uc_attribute/uc_attribute.module
+++ b/uc_attribute/uc_attribute.module
@@ -1273,7 +1273,7 @@ function uc_attribute_option_ajax($form, $form_state) {
 function _uc_attribute_alter_form($id, &$product, $use_ajax) {
   // If the product doesn't have attributes, return the form as it is.
   if (empty($product->attributes) || !is_array($product->attributes)) {
-    return NULL;
+    return array();
   }
 
   $nid = $product->nid;