Need help with a Zend login script

Hi All,

I’m new to Zend and I’m trying to set up a simple user login script with that framework.
Here’s the LoginController.php :

public function processAction()
        $request = $this->getRequest();

        // Check if we have a POST request
        if (!$request->isPost()) {
            return $this->_helper->redirector('index');

        // Get our form and validate it
        $form = $this->getForm();
        if (!$form->isValid($request->getPost())) {
            // Invalid entries
            $this->view->form = $form;
            return $this->render('index'); // re-render the login form

        // Get our authentication adapter and check credentials
        $adapter = $this->getAuthAdapter($form->getValues());
        $auth    = Zend_Auth::getInstance();
        $result  = $auth->authenticate($adapter);
        if (!$result->isValid()) {
            // Invalid credentials
            $form->setDescription('Invalid credentials provided');
            $this->view->form = $form;
            return $this->render('index'); // re-render the login form

        // We're authenticated! Redirect to the home page
        else {
			$this->_helper->redirector('index', 'index');

and the called getAuthAdapter function from the same file :

protected function getAuthAdapter(array $params)
        $dbAdapter = Zend_Db::factory('Pdo_Mysql', array(
                                                'host'     => 'localhost',
                                                'username' => 'root',
                                                'password' => 'my_password_here',
                                                'dbname'   => 'my_db_name_here'

		$authAdapter = new Zend_Auth_Adapter_DbTable($dbAdapter);

	$adapter = $authAdapter;

        $auth = Zend_Auth::getInstance();
        $result = $auth->authenticate($adapter);

        if ($result->isValid()) {
            $user = $adapter->getResultRowObject();
            return true;
        return false;

The problem is when I try to login with CORRECT data, the browser is displaying a blank page and stops at /login/process
When I refresh the page, after I confirm the browser’s dialog box :

To display this page, Firefox must send information that will repeat any action (such as a search or order confirmation) that was performed earlier.

the script renders the index page and I’m logged in.
If I enter invalid login details, the script stops at /login/process and regardless if I refresh the page, it displays a blank page with no content and empty source code… I believe I made some basic mistake and for someone familiar with Zend framework this will be an easy debug (hopefully)… Thank you in advance for your help!!!