Tombol submit dan cancel tidak berfungsi dalam modul baru sikoag ci

Assalamualaikum,.. lampirkan disini mas file dari form yang tombol submitnya tidak berfungsi,
biasanya hal tersebut terjadi hanya karena struktur html yang masih bermasalah.

Assalamualaikum,.. 
ini pesan error tombol submit pak

Assalamualaikum,.. 
ini skrip di administrator pak
 
	// Controller Modul Prestasi
 
	function prestasi(){
		cek_session_akses('prestasi',$this->session->id_session);
        if ($this->session->level=='admin'){
    		$data['record'] = $this->model_app->view_ordering('prestasi','id_prestasi','DESC');
        }else{
            $data['record'] = $this->model_app->view_where_ordering('prestasi',array('username'=>$this->session->username),'id_prestasi','DESC');
        }
		$this->template->load('administrator/template','administrator/mod_prestasi/view_prestasi',$data);
	}
 
	function tambah_prestasi(){
		cek_session_akses('prestasi',$this->session->id_session);
		if (isset($_POST['submit'])){
			$config['upload_path'] = 'asset/foto_prestasi/';
            $config['allowed_types'] = 'gif|jpg|png|JPG|JPEG';
            $config['max_size'] = '3000'; // kb
            $this->load->library('upload', $config);
            $this->upload->do_upload('c');
            $hasil=$this->upload->data();
 
            if ($hasil['file_name']==''){
                    $data = array('tema'->$this->db->escape_str($this->input->post('a')),
                                    'tema_seo'->seo_title($this->input->post('a')),
                                    'isi_prestasi'->$this->input->post('b'),
									'pengirim'->$this->db->escape_str($this->input->post('g')),
                                    'tgl_posting'->date('Y-m-d'),
                                    'username'->$this->session->username);
            }
			else{
                    $data = array('tema'->$this->db->escape_str($this->input->post('a')),
                                    'tema_seo'->seo_title($this->input->post('a')),
                                    'isi_prestasi'->$this->input->post('b'),
									'pengirim'->$this->db->escape_str($this->input->post('g')),
                                    'gambar'->$hasil['file_name'],
                                    'tgl_posting'->date('Y-m-d'),
									'username'->$this->session->username);
            }
            $this->model_app->insert('prestasi',$data);
			redirect('administrator/prestasi');
		}
		else{
			$this->template->load('administrator/template','administrator/mod_prestasi/view_prestasi_tambah');
		}
	}
 
	function edit_prestasi(){
		cek_session_akses('prestasi',$this->session->id_session);
		$id = $this->uri->segment(3);
		if (isset($_POST['submit'])){
			$config['upload_path'] = 'asset/foto_prestasi/';
            $config['allowed_types'] = 'gif|jpg|png|JPG|JPEG';
            $config['max_size'] = '3000'; // kb
            $this->load->library('upload', $config);
            $this->upload->do_upload('c');
            $hasil=$this->upload->data();
 
            if ($hasil['file_name']==''){
                    $data = array('tema'->$this->db->escape_str($this->input->post('a')));
                                    'tema_seo'->seo_title($this->input->post('a'));
                                    'isi_prestasi'->$this->input->post('b');
                                    'pengirim'->$this->db->escape_str($this->input->post('g'));
 
            }
			else{
                    $data = array('tema'->$this->db->escape_str($this->input->post('a')));
                                    'tema_seo'->seo_title($this->input->post('a'));
                                    'isi_prestasi'->$this->input->post('b');
                                    'pengirim'->$this->db->escape_str($this->input->post('g'));
                                    'gambar'->$hasil['file_name'];
 
            }
 
            $where = array('id_prestasi' => $this->input->post('id'));
            $this->model_app->update('prestasi', $data, $where);
			redirect('administrator/prestasi');
		}else{
            if ($this->session->level=='admin'){
			     $proses = $this->model_app->edit('prestasi', array('id_prestasi' => $id))->row_array();
            }else{
                $proses = $this->model_app->edit('prestasi', array('id_prestasi' => $id, 'username' => $this->session->username))->row_array();
            }
 
            $data = array('rows' => $proses);
			$this->template->load('administrator/template','administrator/mod_prestasi/view_prestasi_edit',$data);
		}
	}
 
	function delete_prestasi(){
        cek_session_akses('prestasi',$this->session->id_session);
		if ($this->session->level=='admin'){
            $id = array('id_prestasi' => $this->uri->segment(3));
        }else{
            $id = array('id_prestasi' => $this->uri->segment(3), 'username'=>$this->session->username);
        }
        $this->model_app->delete('prestasi',$id);
		redirect('administrator/prestasi');
	}
 

Assalamualaikum,.. 
kemudian ini file mod_prestasi