Index: includes/form.inc
===================================================================
--- includes/form.inc	(revision 9323)
+++ includes/form.inc	(working copy)
@@ -1538,7 +1538,7 @@
  *   A string representing the form element.
  */
 function theme_form_element($element, $value) {
-  $output  = '<div class="form-item"';
+  $output  = '<div class="form-item'.($element['#required']?' required':'').(form_get_error($element)?' error':'').'"';
   if (!empty($element['#id'])) {
     $output .= ' id="'. $element['#id'] .'-wrapper"';
   }