A note, response from xmlrpc_decode is not always an array. Whenever the XMLRPC server returns a string, xmlrpc_is_fault will complain about not being an array.
Best way to detect errors is
<?php
$response = xmlrpc_decode($file);
if (is_array($response) && xmlrpc_is_fault($response)) {
throw new Exception($response['faultString'], $response['faultCode']);
}
?>