I think I understand..if the file is in the root, it should be:
PHP Code:
<?php
require_once __DIR__ . '/includes/header.php';
?>
If it's one directory deep, it should be:
PHP Code:
<?php
require_once __DIR__ . '/../includes/header.php';
?>
If it's two directories deep, it should be:
PHP Code:
<?php
require_once __DIR__ . '/../../includes/header.php';
?>
etc...
Please confirm this is correct and thank you.