Index: typo3/classes/class.typo3ajax.php
===================================================================
--- typo3/classes/class.typo3ajax.php	(revision 5705)
+++ typo3/classes/class.typo3ajax.php	(working copy)
@@ -203,6 +203,7 @@
 	 * @return	void
 	 */
 	protected function renderAsError() {
+		header('HTTP/1.0 500 AJAX error');
 		header('Content-type: text/xml; charset='.$this->charset);
 		header('X-JSON: false');
 		die('<t3err>'.htmlspecialchars($this->errorMessage).'</t3err>');