Unable to load requested class

[eluser]brixxster[/eluser]
Hello again guys. I need your help again.

I get an error:

Unable to load the requested class: database

I don't know why this is happening since I already autoloaded the database library in the autoload.php under the config folder.

here's my code....

Code:

function updateapp (){
        $this->load->library('database');
        $data['internal_content'] = 'view_update_applicant';
        $data['headTitle']='Applicant Details Updated';
        
        // test the value of the submit button
        $action = $this->input->post('submit');
        if ($action == "Approve")
        {
            echo "aprroved";
        }
        else
        {
            $updatedata = array(
                'fname' => $this->input->post('fname'),
                'lname' => $this->input->post('lname'),
                'mname' => $this->input->post('mname'),
                'email' => $this->input->post('email'),
                'address' => $this->input->post('address'),
                'city' => $this->input->post('city'),
                'province' => $this->input->post('province'),
                'country' => $this->input->post('country'),
                'zip_code' => $this->input->post('zip_code'),
                'cellphone' => $this->input->post('cellphone'),
                'telephone' => $this->input->post('telephone'),
                'acct_id' => $this->input->post('acct_id')
            );
            
            $acct_id = $this->input->post('acct_id');
            
            $updateRec = $this->Model_dbmanagement->update_record($updatedata, $acct_id); // this one is causing the error so I loaded the database library again at the beginning of this function.
            
            $this->session->set_flashdata('action_message', 'Applicant information has been updated.');
            
            $this->appdetails($acct_id);
        }
    }

Hope you guys can help me again..
Thanks.