Does this script work with PHP 5.1.4

[doublet]

I've been having trouble trying to get my shipping working and while reading and browsing I found this:

<?php

$module = fetchDbConfig("USPS");

if($module['status']==1){

/* Demo code for the USPS class, which retrieves real-time shipping quotes for domestic and international shipments, directly from the United States Postal Service. You'll need cURL and DOMXML to use the class. IT DOES NOT WORK WITH PHP 5 */

require "class.usps.php";

Does this mean that Cube Cart does not run on php 5 ? One of the errors I am getting is:

XML error: Invalid documemnt end at line 1 on the 3rd step.

Thank you so much for HELP