session work in localhost but not in my online website

[eluser]7amza[/eluser]
hey how are you dears? wish fine.
i used the Hybrid session library instead of the original coming with CI by default.
so it works fine with me in localhost . but when i upload it , it dosen't work .
i use it to change the style from basic style (for low connexion) to noraml(with pics).
these is my helper (autoload it)

Code:

<?php
function getCurrentStyle(){
    $wadae =& get_instance();        
    $style =  $wadae->session->userdata('currentstyle');
    if(!($style == 'basic')){
    setStyle('');
    return '';
    }
    else{
        $style = 'basic';
    }
    return $style;
}
function setStyle($mode){
    $wadae =& get_instance();    
    $wadae->session->set_userdata('currentstyle',$mode);
}

the controller method:

Code:

function index(){
        //Count Fields
        $data['categoriesField'] = $this->gadget->countField('categories');
        $data['sitesField'] = $this->gadget->countField('sites');
        $data['viewsField'] = $this->gadget->getField('views');
        //categories
        $data['categories'] = $this->category->getCategories();
        //pages
        $data['pages'] = $this->gadget->getPages();
        //adsenses
        $data['adsenses'] = $this->gadget->getAdsenses();
        //blocks
        $data['blocks'] = $this->gadget->getBlocks();
        //articles
        $data['articles'] = $this->article->getArticles(3);
        //load views
        $this->load->view('header',$data);
        $this->load->view('menu',$data);
        $this->load->view(getCurrentStyle().'home',$data);
        $this->load->view('footer',$data);
    }

the switcher method :

Code:

function SetStyle(){
        $mode  =  $this->uri->segment('3');
        if($mode == FALSE){
            redirect($_SERVER['HTTP_REFERER']);
        }elseif($mode == 'basic'){
            setStyle($mode);
        }elseif(!($mode == 'basic')){
            setStyle(NULL);
        }
        redirect($_SERVER['HTTP_REFERER']);
    }

i have to views :
home.php
basichome.php
the link : http://domain.ext/folder/home/SetStyle/basic should change the mode to the basic!
so in localhost it works fine but when i upload it to my online website it don't work !!
any solution?