Trying to get property of non-object [XML]

estou tentando pegar o valor do ip mas da erro "Trying to get property of non-object"

<?php
$xml = simplexml_load_file('http://quest7.myddt.com.br/serverlist.ashx');

echo $xml->Result->Item->ip;
//echo '<pre>';
//var_dump($xml);
?>

xml : http://quest7.myddt.com.br/serverlist.ashx

Notice: Trying to get property of non-object in C:\xampp\htdocs\1.php on line 4

Linha 4 : echo $xml->Result->Item->ip;