archive's post in Redirecting user... was marked as the answer
Use a root based path as you might not know where you are redirecting from:
header('Location: /soapbox/index.php');// same as typing http://localhost/soapbox/index.php #header('Location: /new_page.php'); #header('Location: /index.php'); #header('Location: /soapbox/index.php'); #header('Location: /soapbox/channel/index.php');
archive's post in including that first file in php was marked as the answer
$_SERVER['DOCUMENT_ROOT'] ... defs.php and then add whatever path you are using to get to the defs.php file.
Only have one version of the file, otherwise it will be a nightmare to keep up to date and pointless having it in the first place.