How to fix this error page like this?? im using codeigniter

Question

im having trouble when debug this codeigniter script, please help me to fix this problem guys :(

1. Screenshot page erorr Click here to see my screenshots

2. this is my controller page script (seeing below)

class Admin extends CI_Controller{

function __construct(){
    parent::__construct();
    $this->load->helper(array('form', 'url'));

    if($this->session->userdata('status') != "login"){
        redirect(base_url("login"));
    }

}

function index(){
    $data = array('title' => 'Menu Admin');
    $this->load->view('template/header',$data);
    $this->load->view('template/menu_kiri',$data);
    $this->load->view('Home');
    $this->load->view('template/footer');
}

function absensiswa(){
    $data = array('title' => 'Silahkan isi menu di bawah ini');
    $this->load->view('template/header',$data);
    $this->load->view('template/menu_kiri',$data);
    $this->load->view('menu/absensiswa');
    $this->load->view('template/footer');
}

function tambahkan(){
    $data = array('title'=> 'Menu Pendaftaran siswa baru');
    $this->load->view('template/header',$data);
    $this->load->view('template/menu_kiri');
    $this->load->view('menu/tambahkan');
    $this->load->view('template/footer');
}

public function file_view(){
    $this->load->view('menu/tambahkan', array('error' => ' ' ));
}
public function do_upload(){
    $config['upload_path']          = './uploads/';
    $config['allowed_types']        = 'gif|jpg|png';
    $config['max_size']             = 100;
    $config['max_width']            = 1024;
    $config['max_height']           = 768;

    $this->load->library('upload', $config);

    if ($this->upload->do_upload('userfile'))
    {
        $error = array('error' => $this->upload->display_errors());

        $this->load->view('menu/tambahkan', $error);
    }
    else
    {
        $data = array('upload_data' => $this->upload->data());

        $this->load->view('upload_sukses', $data);
    }

}

function list_siswa(){

    $this->load->helper(array('url'));
    $this->load->model('m_login');
    $this->load->database();
    $jumlah_data = $this->m_login->jumlah_data();
    $this->load->library('pagination');
    $config['base_url'] = base_url().'/admin/list_siswa';
    $config['total_rows'] = $jumlah_data;
    $config['per_page'] = 10;
    /*Class bootstrap pagination yang digunakan*/
    $config['full_tag_open'] = "<ul class='pagination pagination-sm no-margin pull-right'>";
    $config['full_tag_close'] ="</ul>";
    $config['num_tag_open'] = '<li>';
    $config['num_tag_close'] = '</li>';
    $config['cur_tag_open'] = "<li class='disabled'><li class='active'><a href='#'>";
    $config['cur_tag_close'] = "<span class='sr-only'></span></a></li>";
    $config['next_tag_open'] = "<li>";
    $config['next_tagl_close'] = "</li>";
    $config['prev_tag_open'] = "<li>";
    $config['prev_tagl_close'] = "</li>";
    $config['first_tag_open'] = "<li>";
    $config['first_tagl_close'] = "</li>";
    $config['last_tag_open'] = "<li>";
    $config['last_tagl_close'] = "</li>";
    $from = $this->uri->segment(3);
    $this->pagination->initialize($config);     
    $data_table['semua_data'] = $this->m_login->data_tbl($config['per_page'],$from);

    $data = array('title' => 'Ini adalah daftar semua siswa');
    $this->load->view('template/header',$data);
    $this->load->view('template/menu_kiri',$data);
    $this->load->view('menu/list_siswa',$data_table);
    $this->load->view('template/footer');
    //menu pencarian otomatis

}

}

3. This is my view page, i save it in folder menu/tambahkan.php

     <div class="content-wrapper">
  <!-- Content Header (Page header) -->
  <section class="content-header">
    <h1>
      Dashboard
      <small>Control panel</small>
    </h1>
    <ol class="breadcrumb">
      <li><a href="#"><i class="fa fa-dashboard"></i> Home</a></li>
      <li class="active">Dashboard</li>
    </ol>
  </section>

  <?php echo $error;?>

  <?php echo form_open_multipart('admin/do_upload');?>

  <input type="file" name="userfile" size="20" />

  <br /><br />

  <input type="submit" value="upload" />

</form>

<!-- isi konten -->
<section class="content"> 

</section>
</div>

</section>
          </div><!-- /.content-wrapper -->

Helpe guys, i want make upload application on my codeigniter page but is so hard.. i have already trying many script on internet but it did'n work correctly at the last script i bougt it getting bug like that