Failing zmq worker script

worker.php

<?php

require(dirname(__FILE__).'/../lib/zmq/Zmsg.php');

$context = new ZMQContext();
$worker = $context->getSocket(ZMQ::SOCKET_DEALER);
$worker->setSockOpt(ZMQ::SOCKOPT_IDENTITY, trim(`hostname`)."#worker".getmypid());
$worker->connect($endpoint);

// tell the broker we are ready for a test
$worker->send("READY");

// wait till we get a test from the broker
$zmsg = new Zmsg($worker);
$zmsg->recv();

// message is in JSON, decode
$body = $zmsg->body();
$req = json_decode($body);

// tell the broker we have queued the test
$zmsg->body_set("QUEUED $body");
$zmsg->send(false);

// fork a child to execute cmd, in case it crashes
$pid = pcntl_fork();
if ($pid == -1)
{
	die('could not fork');
}
else if ($pid)
{
	// we are the parent
	pcntl_wait($status);
	$exitcode = pcntl_wexitstatus($status);
}
else
{
	// we are the child
	passthru($req->cmd);
	exit(0);
}

$r = array(
	'cmd'=>$req->cmd,
	'exitcode'=>$exitcode,
);

$zmsg->body_set('RESULT '.json_encode($r));
$zmsg->send();