I've noticed that whilst developing on a Windows XP machine with WAMP, $_SERVER['DOCUMENT_ROOT'] returns "/dir/path/". However, on my Unix servers it returns "/dir/path" (no trailing slash).

This becomes a problem as something like the following:

Code PHP:
require($_SERVER['DOCUMENT_ROOT'] . "/header.php");

Works on the Unix server, but not in Windows...

Is this a commonly known difference and what's the best way to get around it?