I posted another thread in the PHP section here: http://webdeveloper.com/forum/showthread.php?t=243764
I just realized that its probably not a PHP error, it's probably a server error.
http://linksku.com/button.php is loading just fine but http://linksku.com/button.php?url=http://www.example.com is returning a 404 not found error.
I have no idea what's wrong. My host still haven't responded yet.