problem with password checking

[eluser]cideveloper[/eluser]
Also don't post all your code. Only post the relevant sections. That is just lazy. Also you post every single line but I don't see a function that is called when calling "callback_username_check"

P.S. This is a fix for the question not the answer

Code:

<?php
class Account extends Controller
{
    function Account()
    {
        parent::Controller();
        $this->load->library(array('form_validation', 'session'));
        $this->load->helper(array('url', 'form'));
        $this->load->model('account_model');
        $this->_salt = "123456789987654321";
    }


    function login()
    {
        $this->form_validation->set_rules('username', 'Username','xss_clean|required|callback_username_check');
        $this->form_validation->set_rules('password', 'Password','xss_clean|required|min_length[4]|max_length[12]|sha1|callback_password_check');
        $this->_username = $this->input->post('username');
        $this->_password =sha1($this->_salt.$this->input->post('password'));

        if($this->form_validation->run() == FALSE)
        {
            $this->load->view('account/login');
        }
        else
        {
            $this->account_model->login();
            $data['message'] = "You are logged in! Now go take a look at the ". anchor('account/dashboard', 'Dashboard');
            $this->load->view('account/success', $data);
        }
    }


    function password_check()
    {
        $this->db->where('username', $this->_username);

        $query = $this->db->get('users');
        $result = $query->row_array();
        if($query->num_rows() == 0)
        {
            $this->form_validation->set_message('password_check', 'username not found!');
            return FALSE;
        }
        if($result['password']==$this->_password);
        {
            return TRUE;
        }
    }

}
?>