Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 4996)
+++ wp-includes/functions.php	(working copy)
@@ -1333,6 +1333,7 @@
 	}
 
 	header('Content-Type: text/html; charset=utf-8');
+	header("HTTP/1.1 500 Internal Server Error");
 
 	if ( empty($title) )
 		$title = __('WordPress › Error');
Index: wp-includes/wp-db.php
===================================================================
--- wp-includes/wp-db.php	(revision 4996)
+++ wp-includes/wp-db.php	(working copy)
@@ -371,6 +371,7 @@
 			return false;
 
 		header('Content-Type: text/html; charset=utf-8');
+		header("HTTP/1.1 500 Internal Server Error");
 
 		if (strpos($_SERVER['PHP_SELF'], 'wp-admin') !== false)
 			$admin_dir = '';