Index: modules/field_ui/field_ui.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/field_ui/field_ui.admin.inc,v
retrieving revision 1.10
diff -u -p -r1.10 field_ui.admin.inc
--- modules/field_ui/field_ui.admin.inc	29 Aug 2009 07:43:58 -0000	1.10
+++ modules/field_ui/field_ui.admin.inc	5 Sep 2009 10:47:27 -0000
@@ -1285,7 +1285,7 @@ function field_ui_field_edit_form_submit
 
   // Move the default value from the sample widget to the default value field.
   if (isset($instance_values['default_value_widget'])) {
-    $langcode = $instance_values['default_value_widget'][$field_name]['#language'];
+    $langcode = $form['instance']['default_value_widget'][$field_name]['#language'];
     $instance_values['default_value'] = $instance_values['default_value_widget'][$field_name][$langcode];
     unset($instance_values['default_value_widget']);
   }