Ops, my bad.
its in global.php:define('MEDIA_PATH', ROOT_PATH.MEDIA_DIR);
define('THUMB_PATH', ROOT_PATH.THUMB_DIR);
define('MEDIA_TEMP_PATH', ROOT_PATH.MEDIA_TEMP_DIR);
define('THUMB_TEMP_PATH', ROOT_PATH.THUMB_TEMP_DIR);
define('TEMPLATE_PATH', ROOT_PATH.TEMPLATE_DIR."/".$config['template_dir']);
define('ICON_PATH', ROOT_PATH.TEMPLATE_DIR."/".$config['template_dir']."/icons");
replace ROOT_PATH with your own relative path i.e.: "../" (including quotes!)