Hi Lenny,
I've you've installed PHP correctly according to the manual, this script should work. It's basically the most simple script you could have...
Try to create a php-script like this:
<head></head>
<body>
<?php echo("Yes, it works!!!!");?>
</body>
and name it simple.php and try it to see if it works. If it doesn't show "Yes, it works!!!!" something's wrong with your installation. If it does, your own script should work too.
Let us know!
Maarten