updating a sql row

[aebstract]

[code]<?php
if(isset($HTTP_POST_VARS['usern'])) {
$usern = strip_tags($HTTP_POST_VARS['usern']);
$passw = strip_tags($HTTP_POST_VARS['passw']);
setcookie("Username",$usern);
setcookie("Password",$passw);
$lastloginip = $_SERVER['REMOTE_ADDR'];
require('dblogon.php');
$query = "UPDATE userinf SET lastloginip=$lastloginup WHERE username=$usern";
$r = mysql_query ($query);

header("Location: member.php");
exit();
}[/code]


Could someone tell me why it isn't updating lastloginip that matches my username when I log in to this website?
Thanks