PHP中RETS数据获取源的问题

我正在使用PHRETS PHP库从RETS API获取RETS数据。我对获取数据有意见。它给了我未找到请求类的错误。请帮助解决此错误。我的代码是：

date_default_timezone_set('America/New_York');
require_once("vendor/autoload.php");
$log = new 'Monolog'Logger('PHRETS');
$log->pushHandler(new 'Monolog'Handler'StreamHandler('php://stdout', 'Monolog'Logger::DEBUG));

$config = new 'PHRETS'Configuration;
$config->setLoginUrl('http://rets.navicamls.net/login.aspx')
        ->setUsername('xxx')
        ->setPassword('xxx')
        ->setRetsVersion('1.7.2');
$rets = new 'PHRETS'Session($config);
$rets->setLogger($log);
$connect = $rets->Login();

if ($connect) {
 echo "Connected!<br>";
}
else {
 echo "Not Connected!<br>";
 print_r($rets->Error());
 exit;
}

//results consists of Property, class, and query
$results = $rets->Search(
    "Property",
    "A",
    "*",
    [
        'QueryType' => 'DMQL2',
        'Count' => 1, // count and records
        'Format' => 'COMPACT-DECODED',
        'Limit' => 10,
        'StandardNames' => 0, // give system names
    ]
);
print_r($results); exit;