[SOLVED] Need help for multilanguage site

[eluser]Unknown[/eluser]
Hi all,
i want to make the site with multi languages and selecting the language with ajax and the different words will be selected from database and i want to use session[lang],and i don't want to use GET[lang].
i'm trying from 5 days to make this but i try so many variants and i'm confused now

now i'm here:

i have model -> Langs ->
function set_langs($arg) {
$this->session->unset_userdata('lang');
$this->session->set_userdata('lang', $arg);
return $arg;
}
function get_langs() {
return $this->session->userdata('lang');
}

in the Home controller ->
public function index(){
if($this->session->userdata('lang')==''){
$this->Langs->set_langs('en');
$glang['lang'] = $this->Langs->get_langs();
}else{
$glang['lang'] = $this->Langs->get_langs();
}
$this->load->view('header', $glang);
}
public function set()
{
if($_POST && $_POST['lang'] != NULL) {
$this->Langs->set_langs($_POST['lang']);
$return['error'] = false;
$return['msg'] = $this->session->userdata('lang').' ok!';
echo json_encode($return);
}else{...}
}

and in the header.php -> in the JS ->
$.ajax({
type: "POST",
url: "index.php/home/set",
dataType : 'json',
data: "lang="+lang,
success: function(data){
if(data.error === true){
$( "#dialog-message2" ).text(data.msg).dialog({
modal: true,
buttons: {
Ok: function() {
$( this ).dialog( "close" );[removed]=location.href;
}
}
});
}else{...}

when the page refresh the language stil not changed but when return the message from ajax it work
so where im wrong
sorry for the bad english
thanks


*** the problem was -> system/libraries/Session.php (the original file from the CodeIgniter_2.0.2.zip) -> i download http://codeigniter.com/wiki/File:CI_1.5....ssion.zip/ and no problems