diff --git a/commerce_coupon.module b/commerce_coupon.module
index bda80a2..d369c32 100644
--- a/commerce_coupon.module
+++ b/commerce_coupon.module
@@ -230,7 +230,7 @@ function commerce_coupon_code_is_valid($code, $order) {
 
   // if no such coupon found, the $code is invalid
   if (!is_object($coupon)) {
-   // $commerce_coupon_validation_error_message = t('Coupon code is invalid.');
+    $_commerce_coupon_validation_error_message = t('Coupon code is invalid.');
     return FALSE;
   }