无法使用cakephp登录

Question

I am using the Auth component and login functionality in my application. But whenever I try to login, it gives me an invalid username and password error.

And it also throws also a warning like:

Warning (2): Invalid argument supplied for foreach() [CORE\Cake\Utility\Hash.php, line 51]

This is my login function:-

public function login() {
    if ($this->request->is('post')) {
        if ($this->Auth->login()) {
            $this->redirect($this->Auth->redirect());
        } else {
            $this->Session->setFlash(__('Invalid username or password, try again'));
        }
    }
}

Any help on this? I don't understand what the problem is. Thanks in advance.

Updated: Here is the code from my AppController.

public $components = array(
    'Session',
    'Auth' => array(
        'loginRedirect' => array('controller' => 'woods', 'action' => 'index'),
        'logoutRedirect' => array('controller' => 'users', 'action' => 'add')
    )
);