diff --git a/commerce_flat_rate.i18n.inc b/commerce_flat_rate.i18n.inc
index ec062b5..e2fa210 100644
--- a/commerce_flat_rate.i18n.inc
+++ b/commerce_flat_rate.i18n.inc
@@ -60,6 +60,10 @@ function commerce_flat_rate_i18n_string_objects($type) {
  * @see commerce_flat_rate_i18n_string_locale_translate_edit_form_submit()
  */
 function commerce_flat_rate_i18n_string_locale_translate_edit_form_submit($form, &$form_state) {
+  if (!isset($form_state['values']['i18n_string'])) {
+    return;
+  }
+
   $i18n_string = $form_state['values']['i18n_string'];
   if (is_object($i18n_string) && 'commerce_flat_rate' == $i18n_string->textgroup) {
     // Remove the Flat Rate service associated to the current translation from