Description:
------------
On the manual page:
http://nl2.php.net/manual/en/function.unlink.php
the Examples show: 
Basic unlink() usage: 
<?php 
$fh = fopen('test.html', 'a'); 
fwrite($fh, '<h1>Hello world!</h1>'); 
fclose($fh); 
mkdir('testdir', 0777); 
unlink('test.html'); 
unlink('testdir'); 
?> 

But unlink is not valid for a directory (php issues a warning and does not delete 
the directory)