php - codeigniter tank_auth error in userinterface page -

my login interface starts error message.

a php error encountered
severity: notice
message: undefined variable: login_by_username
filename: auth/register_form.php
line number: 10
php error encountered
severity: notice
message: undefined variable: login_by_username
filename: auth/register_form.php
line number: 12

if press login button without out passing values , tank_auth doesn't promt me error.instead redirected me welcome page error.

hi,
php error encountered
severity: notice
message: undefined variable: username
filename: views/welcome.php
line number: 3
! logged in now. logout
auth.php file

  function login()       {           if ($this->tank_auth->is_logged_in()) {                                     // logged in         redirect('');       } elseif ($this->tank_auth->is_logged_in(false)) {                      // logged in, not activated          redirect('/auth/send_again/');      } else {          $data['login_by_username'] = ($this->config->item('login_by_username', 'tank_auth') ,                 $this->config->item('use_username', 'tank_auth'));         $data['login_by_email'] = $this->config->item('login_by_email', 'tank_auth');          $this->form_validation->set_rules('login', 'login', 'trim|required|xss_clean');         $this->form_validation->set_rules('password', 'password', 'trim|required|xss_clean');         $this->form_validation->set_rules('remember', 'remember me', 'integer');          // login counting attempts login         if ($this->config->item('login_count_attempts', 'tank_auth') ,                 ($login = $this->input->post('login'))) {             $login = $this->security->xss_clean($login);         } else {              $login = '';         }          $data['use_recaptcha'] = $this->config->item('use_recaptcha', 'tank_auth');         if ($this->tank_auth->is_max_login_attempts_exceeded($login)) {             if ($data['use_recaptcha'])                 $this->form_validation->set_rules('recaptcha_response_field', 'confirmation code', 'trim|xss_clean|required|callback__check_recaptcha');             else                 $this->form_validation->set_rules('captcha', 'confirmation code', 'trim|xss_clean|required|callback__check_captcha');         }         $data['errors'] = array();          if ($this->form_validation->run()) {                                // validation ok             if ($this->tank_auth->login(                     $this->form_validation->set_value('login'),                     $this->form_validation->set_value('password'),                     $this->form_validation->set_value('remember'),                      $data['login_by_username'],                     $data['login_by_email'])) {                             // success                  redirect('');              } else {                 $errors = $this->tank_auth->get_error_message();                 if (isset($errors['banned'])) {                             // banned user                     $this->_show_message($this->lang->line('auth_message_banned').' '.$errors['banned']);                  } elseif (isset($errors['not_activated'])) {                // not activated user                     redirect('/auth/send_again/');                  } else {                                                    // fail                     foreach ($errors $k => $v)   $data['errors'][$k] = $this->lang->line($v);                     echo "test6";                 }             }         }         $data['show_captcha'] = false;         if ($this->tank_auth->is_max_login_attempts_exceeded($login)) {             $data['show_captcha'] = false;//captcha on , off control true show captcha.............sajad.             if ($data['use_recaptcha']) {                 $data['recaptcha_html'] = $this->_create_recaptcha();             } else {                 $data['captcha_html'] = $this->_create_captcha();             }         }                      $data['title']= 'home';         $this->load->view('header_view',$data);         $this->load->view('welcome', $data);         $this->load->view('footer_view',$data);      } }  register_form.php file.       <?php       $login = array(       'name'  => 'login',       'id'    => 'login',       'value' => set_value('login'),        'maxlength' => 80,       'size'  => 30,   );   if ($login_by_username , $login_by_email) {                       $login_label = 'email or login';                   } else if ($login_by_username) {                       $login_label = 'login';                   } else {                       $login_label = 'email';                   }    $password = array(       'name'  => 'password',       'id'    => 'password',       'size'  => 30,   );   $remember = array(       'name'  => 'remember',       'id'    => 'remember',       'value' => 1,       'checked'   => set_value('remember'),       'style' => 'margin:0;padding:0',   );   $captcha = array(       'name'  => 'captcha',       'id'    => 'captcha',       'maxlength' => 8,   );?>                           <?php echo form_open('auth/login'); ?><br /><br />      <?php echo form_label('login', $login['id']); ?>     <?php echo form_input($login); ?>     <?php echo form_label('password', $password['id']); ?>     <?php echo form_password($password); ?>     <?php echo form_submit('submit', 'let me in'); ?><br /><br />      <?php echo form_error($login['name']); ?><?php echo isset($errors[$login['name']])?    $errors[$login['name']]:''; ?>    <?php echo form_error($password['name']); ?><?php echo isset($errors[$password['name']])?$errors[$password['name']]:''; ?>     <?php echo form_close(); ?>   

please upload version of following files:
1) auth/register_form.php
2) views/welcome.php

-- seekers01