Multiple file upload library

[eluser]pierrest[/eluser]
Hello everybody,

This library was workin perfect on my dev server, but now just deploying my project to the production server and i get this message

Call to undefined method CI_Upload::up()

my controller:

Code:

<?php

class Upload extends CI_Controller {

function __construct()
{
  parent::__construct();
  $this->load->helper(array('form', 'url'));
}

function index()
{
  $this->load->view('admin/modify_module', array('error' => ' ' ));
  
  $this->load->library('session');
  $this->load->library('encrypt');
  $this->data['username'] = $this->session->userdata('user');
}
function do_upload_member() {
   $this->load->library('upload');

   $config['upload_path']   = './uploads'; //if the files does not exist it'll be created
   $config['allowed_types'] = 'gif|jpg|png|xls|xlsx|php|pdf';
   $config['max_size']   = '4000'; //size in kilobytes
   $config['encrypt_name']  = TRUE;

   $this->upload->initialize($config);

   $uploaded = $this->upload->up(TRUE); //Pass true if you want to create the index.php files

  $this->load->model('members');
   if ($this->input->post('submit')) {
    $this->members->add_member($uploaded);
   }
  $data['pagetitle'] = " Adhésion";
  $data['pageref'] = 'Nous avons bien reçu votre demande';
  $this->load->view('head', $data);
  $this->load->view('confirmation');
}



}
?>

have been for a while on it and i am lost...

i have some rewriting htaccess stuff too which was not on the dev server:
(there is an evil joomla project on the same sever (which i did not develop myself) i use a subdomain for CI)

php_flag "allow_url_fopen" "On"
php_flag "allow_url_include" "On"

#AuthType Basic
#AuthName "Le site est en maintenance, veuillez repasser plus tard"
#AuthUserFile /home/www/c5f672d79af39528e95ff68c3587e35e/web/members/.htpasswd

#<Files index.php>
#require valid-user
#</Files>

RewriteEngine on
RewriteCond $1 !^(index\.php|resources|robots\.txt)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L,QSA]


is it this rewrite which may causing the problem?

Thanks a lot if you can help me