diff --git a/setup/inc/functions.inc.php b/setup/inc/functions.inc.php
index e24cbd8a9f..9e8d69c45f 100644
--- a/setup/inc/functions.inc.php
+++ b/setup/inc/functions.inc.php
@@ -25,9 +25,9 @@ $GLOBALS['egw_info'] = array(
 		'currentapp' => 'setup',
 		'noapi' => True
 ));
-if(file_exists('../header.inc.php'))
+if(file_exists(__DIR__.'/../../header.inc.php'))
 {
-	include('../header.inc.php');
+	include_once(__DIR__.'/../../header.inc.php');
 }
 // for an old header we need to setup a reference for the domains
 if (!is_array($GLOBALS['egw_domain'])) $GLOBALS['egw_domain'] =& $GLOBALS['phpgw_domain'];