Codeigniter using active record and sql injection

I have using Active Record in my Codeigniter apps. But still got error, I think it cause by sql injection

function get_member_by_hape($hape)
{
    $this->db->select('*');
    $this->db->from('member');
    $this->db->where('hape',$hape);

    $query = $this->db->get();
    if ($query->num_rows() > 0){
        return $query->row_array();
    }else{
        return FALSE;
    }
}

I tried so far, it is no problem. But there is someone who tells me about the error http://ift.tt/1KCisHG on login form. I don't know where is the problem on my source code. This is my website pulsa.aijogja.com