Any one see a problem with this ?

Ive been working with these files for 5 hours today, ive got nearly all of them sorted but this one is killing me

Im getting this error :

Code (text):

Notice: Undefined index: id in /home/bretr/public_html/freehostout.php on line 4

This is the code :

PHP:

<?php
error_reporting (E_ALL);
require_once ("./includes/config.php");
$hostid = $_GET['id'];
$getfreehosthits = "SELECT Hits, HostingURL FROM freehosting WHERE HostingId='". $hostid ."'";
$freehosthitsrs = mysql_query($getfreehosthits, $conn) or die (mysql_errno() . ": " . mysql_error()). "\n";
while($freehosthits = mysql_fetch_array($freehosthitsrs))
{
    $hits = $freehostinghits['Hits'];
    $url = $freehostinghits['HostingURL'];
    $newhits = $hits + 1;
    $updatehits = mysql_query("UPDATE freehosting SET Hits='". $newhits."' WHERE HostingId='". $hostid ."'");
    mysql_query($updatehits, $conn);
}
mysql_free_result($freehosthitsrs);
mysql_close($conn);
header("Location:". $url. "");
exit();
?>
 

Any ideas ?

Thanks bud , got it sorted in the end. All is working , site is nearly ready to go