v 1.3.3 grocery CRUD - an automatic Codeigniter CRUD

[eluser]ReyPM[/eluser]
Ok, I've found this amazing tool and trying to use in my development but I'm doing something wrong because don't work. See what I've done until now:
1. Load needed libraries in __construct() (The other libraries needed are autoloaded).

Code:

public function __construct() {
      parent::__construct();
      $this->load->add_package_path(APPPATH . 'third_party/grocery_crud/');
      $this->output->set_template('custom_cms');
      $this->load->library('grocery_CRUD');
}

2. Write this piece of code in index():

Code:

public function index() {
      if ($this->my_usession->logged_in) {
      $this->grocery_crud->set_table('trasegados')
                 ->set_subject('Trasegados')
                 ->columns('inicio_91', 'fin_91', 'total_91', 'inicio_95', 'fin_95', 'total_95', 'inicio_diesel', 'fin_diesel', 'total_diesel', 'id_estacion', 'usuario');
         $this->grocery_crud->fields('inicio_91', 'fin_91', 'total_91', 'inicio_95', 'fin_95', 'total_95', 'inicio_diesel', 'fin_diesel', 'total_diesel', 'id_estacion', 'usuario');
         $this->grocery_crud->required_fields('inicio_91', 'fin_91', 'total_91', 'inicio_95', 'fin_95', 'total_95', 'inicio_diesel', 'fin_diesel', 'total_diesel', 'id_estacion', 'usuario');
         $this->grocery_crud->render();
         $this->load->view('trasegados/form', $data);
      } else {
         redirect('user/login');
      }
   }

3. Echo $output at trasegados/form template:

Code:

<?php $this->load->view('layout_login_header'); ?>
<?php echo $output ?>
<?php $this->load->view('layout_login_footer'); ?>

4. Add the needed code at layout_login_header:

Code:

<?php foreach ($css as $file): ?>
      <link type="text/css" rel="stylesheet" href="<?php echo $file; ?>" />
      <?php endforeach; ?>
      [removed]var base_url = '<?= base_url() ?>';[removed]
      <?php foreach ($js as $file): ?>
         [removed][removed]
      <?php endforeach; ?>

But I got a lot of errors:

A PHP Error was encountered

Severity: Notice

Message: Undefined variable: css

Filename: views/layout_login_header.php

Line Number: 11

A PHP Error was encountered

Severity: Warning

Message: Invalid argument supplied for foreach()

Filename: views/layout_login_header.php

Line Number: 11
A PHP Error was encountered

Severity: Notice

Message: Undefined variable: js

Filename: views/layout_login_header.php

Line Number: 15
A PHP Error was encountered

Severity: Warning

Message: Invalid argument supplied for foreach()

Filename: views/layout_login_header.php

Line Number: 15

See the entire output image here http://www.dropmocks.com/mUTRR. Why this? What I'm doing wrong?

Cheers and thanks