Flash multiple upload doesn't work with CI upload library

[eluser]Unknown[/eluser]
Hi,

I'm trying to do my own multiple file upload form using flash. I have prepared swf and controller.
If my action looks like this:

Code:

public function upload()
{
     move_uploaded_file($_FILES['userfile']['tmp_name'],'./uploads/'.time().$_FILES['userfile']['name']);
}

everything works perfect - the file is uploading.
But when i change action to (http://ellislab.com/codeigniter/user-gui...ading.html):

Code:

public function upload()
{
     $config['upload_path'] = './uploads/';
    
     $this->load->library('upload');
     if ( ! $this->upload->do_upload('userfile'))
     {
        return 0;
     }    
     else
     {
        return 1;
     }
}

it doesn't work any more.

Furthermore second option works fine with HTML form.

I'm a little bit confused.
Any ideas?