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']);
    }
    
?>