Redirect code problem

Hi All, I'm having a small problem with a piece of code that I'm using to redirect a page through a script, but only if it isn't already. The script itself strips the path and query info from the request before passing it to PHP, so I'm stuck using HTTP_REFERER to trigger it. <?php $ref = explode("/", $GLOBALS["HTTP_REFERER"]); if (!$ref[4] == "script.exe") { header ("Location: http://www.myserver.com/cgi-bin/script.exe$PHP_SELF?arg1+arg2"); exit; } ?> This works great with files in a second level directory, such as: http://www.myserver.com/folder/page.html but it gets stuck in a loop with root level files, such as: http://www.myserver.com/page.html presumably because $ref[4] doesn't exist. Can anyone think of a way to improve this so that it can work with multi-level files? I've tried a few things out without success, so I'm stuck here head scratching. cheers, Richard