When using the new Zend_Loader_AutoloaderFactory with ClassMap Autoloader before the Standard Autoloader, the application falls over with the error:

Autoloader class "Zend_Loader_ClassMapAutoloader" not loaded

include 'Zend/Loader/AutoloaderFactory.php';
 $config = array(
        'Zend_Loader_ClassMapAutoloader' => array(
            './library/autoload_classmap.php',
            './application/autoload_classmap.php'
        ),
        'Zend_Loader_StandardAutoloader' => array(
            'prefixes' => array(
                'My_'       => 'My',
                'Zend_'     => 'Zend',
                'ZendX_'    => 'ZendX',
            ),
            'fallback_autoloader' => true,
        ),
    );

    Zend_Loader_AutoloaderFactory::factory($config);

Adding the following:

include 'Zend/Loader/ClassMapAutoloader.php';

before the

Zend_Loader_AutoloaderFactory::factory($config);

line fixes the issue.