Creating mongo configuration class instance hangs php

After pasting down the doc tutorial example I've noticed that php hangs on
Configuration instance creation.

require 'Doctrine/Common/ClassLoader.php';
use Doctrine\Common\ClassLoader,
Doctrine\Common\Annotations\AnnotationReader,
Doctrine\ODM\MongoDB\DocumentManager,
Doctrine\ODM\MongoDB\Mongo,
Doctrine\ODM\MongoDB\Configuration,
Doctrine\ODM\MongoDB\Mapping\Driver\AnnotationDriver;
// ODM Classes
$classLoader = new ClassLoader('Doctrine\ODM', 'mongodb_odm/lib');
$classLoader->register();
// Common Classes
$classLoader = new ClassLoader('Doctrine\Common', 'mongodb_odm/lib/vendor/doctrine-common/lib');
$classLoader->register();
// Document classes
$classLoader = new ClassLoader('Documents', _DIR_);
$classLoader->register();

//-------hangs here
$config = new Configuration();

//tried explicit too
// new Doctrine\ODM\MongoDB\Configuration();

No errors or warnigs of any kind generated.