Index: modules/taxonomy/taxonomy.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/taxonomy/taxonomy.module,v
retrieving revision 1.503
diff -u -p -r1.503 taxonomy.module
--- modules/taxonomy/taxonomy.module	24 Aug 2009 00:14:22 -0000	1.503
+++ modules/taxonomy/taxonomy.module	24 Aug 2009 14:21:52 -0000
@@ -2213,7 +2213,9 @@ function taxonomy_autocomplete_elements_
 function taxonomy_autocomplete_validate($element, &$form_state) {
   // Autocomplete widgets do not send their tids in the form, so we must detect
   // them here and process them independently.
-  if ($form_state['values'][$element['#field_name']]['value']) {
+  $field_name = $element['#field_name'];
+  $langcode = $form_state['complete form'][$field_name]['#language'];
+  if ($tags = $form_state['values'][$field_name][$langcode]['value']) {
 
     // @see taxonomy_node_save
     $field = $form_state['#fields'][$element['#field_name']]['field'];
@@ -2222,7 +2224,7 @@ function taxonomy_autocomplete_validate(
     foreach ($field['settings']['allowed_values'] as $tree) {
       $vids[] = $tree['vid'];
     }
-    $typed_terms = drupal_explode_tags($form_state['values'][$element['#field_name']]['value']);
+    $typed_terms = drupal_explode_tags($tags);
     $values = array();
 
     foreach ($typed_terms as $typed_term) {