ZendX_JQuery_Form_Element_DatePicker doesn´t work

My datepicker doesn't work. I don't get any errors and instead of the datepicker appearing, my field looks like a dropdown and shows the formerly used dates.

I added to my bootstrap:

protected function _InitAutoload()
    {
        $view= new Zend_View();
        $viewRenderer = new Zend_Controller_Action_Helper_ViewRenderer();
        $view->addHelperPath(’ZendX/JQuery/View/Helper/’, ‘ZendX_JQuery_View_Helper’);
        $viewRenderer->setView($view);
        Zend_Controller_Action_HelperBroker::addHelper($viewRenderer);
    }

I changed my datefield in my formclass like follows:

$datum= new ZendX_JQuery_Form_Element_DatePicker("datum", '',
                    array('defaultDate' => date('Y/m/d', time()))); 

My formclass extends ZendX_JQuery_Form.

In my layout.phtml I added:

$this->jQuery()->setLocalPath('http://localhost/zend/js/jquery/jquery-1.2.6.js')
 ->addStylesheet('http://localhost/zend/js/jquery/themes/ui.datepicker.css');
echo $this->jQuery();

Where is my error? Is there something missing somewhere?