dbsession problem

[eluser]dimis[/eluser]
I use dbsession and CI 1.7.
I have a MY_controller with this code

Code:

function Islogin()
    {
         $this->object =& get_instance();
        if ( $this->object->db_session->userdata('userid')!='1')
        {
            return false;
        }
        else
        return true;

    }

My problem is that now when I login and navigate at my "manager"< when I try to post a form I am redirecting at login page (lost sesion?).Yesterday I put at code some models,controllers and views from a CI 1.6.3 setup, this problem were not here before.
What is the problem?

[eluser]dimis[/eluser]
At one controller I solved it, it was related with the code.
Dimis