Для консольных скриптов

xml_downloader.php

$_SERVER["DOCUMENT_ROOT"] = '/home/bitrix/www';

define("NO_KEEP_STATISTIC", true);
define("NO_AGENT_STATISTIC","Y");
define("NO_AGENT_CHECK", true);
define("DisableEventsCheck", true);
define("NOT_CHECK_PERMISSIONS",true);

require($_SERVER["DOCUMENT_ROOT"]."/bitrix/modules/main/include/prolog_before.php");
if(!defined("B_PROLOG_INCLUDED") || B_PROLOG_INCLUDED!==true)die();