第一次请求后，SOAP客户端抛出“获取http标头时出错”

I need to make the acquaintance of SOAP, and wrote a simple client connecting to some random web service. (Turns out even finding a working service is a bit of a hassle.)

The code I have so far seems to work - but here's the thing: it only works once every ten seconds.

When I first load the page it shows the result I expect - a var_dump of an object - but when I reload the page right after that, all I see is Error Fetching http headers. Now matter how many times I refresh, it takes around ten seconds until I get the right result again, and then the process repeats - refresh too quickly, get an error.

I can't see what's going on at the HTTP level, and even if I could, I'm not sure I'd be able to draw the right conclusions.
Answers to similar questions posted here include setting the keep_alive option to false, or extending the default_socket_timeout, but neither solution worked for me.

So, long story short: is this an issue on the service's end or a problem I can remedy, and if it's the latter, how?
Here's the code I got so far:

<?php

    error_reporting(-1);
    ini_set("display_errors", true);
    ini_set("max_execution_time", 600);
    ini_set('default_socket_timeout', 600);

    $wsdl = "http://api.chartlyrics.com/apiv1.asmx?WSDL";

    try
    {
        $client = new SoapClient($wsdl, array(
            "keep_alive" => false,
            "trace" => true
        ));

        $response = $client->SearchLyricDirect(array(
            "artist" => "beatles",
            "song" => "norwegian wood"
        ));
        var_dump($response);
    }
    catch (Exception $e)
    {
        echo $e->getMessage();
    }

?>

Any help would be appreciated. (And as a bonus, if you could enlighten me as to why saving the WSDL locally speeds the process up by 30 seconds, that'd be great as well. I assume it's the DNS lookup that takes so much time?)

As it turns out, the connection to the server as a whole is rather shaky.
I (and a few others I've asked to) had similar issues just trying to open the WSDL file in a browser - it works the first time, but refreshing somehow aborts the connection for a good ten seconds.

Though I really can't say what its problem is, this does strongly suggest that the fault lies with the server, not my client.