Cant retrieve session item

[eluser]Dileep[/eluser]
Hello there ,

I am using uploadify uploader for uploading images/files.

But on a particular place i cant retrieve the 'username' from session.

Here my controller.

Code:

function uploadFile()
    {
    require_once('class.upload.php');
if (!empty($_FILES)) {
         $uc = $this->session->userdata('username');
         //$_REQUEST['folder'] = "/pro/user/Dileepmt/pages/".$_REQUEST['folder']."/images/background";
         $_REQUEST['folder'] = $uc."/pro/user/".$uc."/pages".$_REQUEST['folder']."/images/background";
        $targetPath = $_SERVER['DOCUMENT_ROOT'] .$_REQUEST['folder']. '/';
        $pic_temp = random_string('alnum',10);

        $handle = new Upload($_FILES['Filedata']);
            if ($handle->uploaded) {
                $handle->file_src_name_body      = $pic_temp; // hard name
                $handle->file_overwrite          = true;
                $handle->file_auto_rename        = false;
                $handle->image_resize            = true;
                $handle->image_ratio_y           = true;
                $handle->image_x                 = ($handle->image_src_x < 400)?$handle->image_src_x:400;
                $handle->file_max_size           = '819200'; // max size
                $handle->Process($targetPath);
                $handle->clean();
                if ($handle->processed)
                    $json = array("result"      => 1,
                                  "file"        => $_REQUEST['folder'].'/'.$handle->file_dst_name.'?'.time(),
                                  "imagewidth"  => $handle->image_dst_x,
                                  "imageheight" => $handle->image_dst_y
                                 );
                else
                    $json = array("result" => 0);

                $encoded = json_encode($json);
                echo $encoded;
                unset($encoded);    
            }
            else {
                $json = array("result" => 0);
                $encoded = json_encode($json);
                echo $encoded;
                unset($encoded);
            }
}


    }

Uploadify have so many problems but here i am failed to retrieve the session data using Codeignitor session library.

Code:

$uc = $this->session->userdata('username');

$_REQUEST['folder'] = $uc."/pro/user/pages".$_REQUEST['folder']."/images/backgroun

d";

assume that username = >'myuser' and 'folder' = >'myfolder'

so

Code:

$_REQUEST['folder']

will be

myuser/pro/user/pages/myfolder/images/background

But the result is

/pro/user/pages/myfolder/images/background

I checked there is no problem with Codeignitor session , i can set or retrieve data by using session library.

Please help me.

Thank you .