Login com CodeIgniter

[Paulo Amaral]

Olé estou começando com CodeIgniter, e já tenho problema no login do sistema.
Apos inserir os dados nos campos "nome" e "senha" e submeter o formulário me retorna os seguintes erros:


A PHP Error was encountered
Severity: Warning
Message: Cannot modify header information - headers already sent by (output started at C:\xampp\htdocs\automac\system\database\drivers\mysqli\mysqli_driver.php:221)
Filename: core/Common.php
Line Number: 569
Backtrace:


A PHP Error was encountered
Severity: Error
Message: Maximum execution time of 60 seconds exceeded
Filename: mysqli/mysqli_driver.php
Line Number: 221
Backtrace:

segue os códigos

login_model.php(Model)

	if (! defined('BASEPATH')) exit('No direct script access allowed');
	
	class Login_model extends CI_Model {
		
		//Validação do usuário		
		public function validacao($usuario, $senha){
			
			$this->db->where('USUARIO', $usuario);
			$this->db->where('SENHA', $senha);
			
			$query = $this->db->get('DBA');
			
			
			if($query->num_rows == 1){
				print_r($query);
				die();	
				return true; // retorna verdadeiro
			}
		}
		
		//Verifica se usuário esta logado
		public function logado(){
			$logado = $this->session->userdata('logado');
			
			if(!isset($logado) || $logado != true){
				echo 'Voce nao tem permissao para entrar nessa pagina!';
            	die();
			}
		}
	}

login.php(Controller)

	if (! defined('BASEPATH')) exit('No direct script access allowed');
	class Login extends CI_Controller{
		function __construct(){
			parent:: __construct();
		}
		
		public function index(){
			
			//Validacao
			$this->load->library('form_validation');
			$this->form_validation->set_rules('usuario', 'Usuário', 'required');
			$this->form_validation->set_rules('senha', 'Senha', 'required');
			$this->form_validation->set_error_delimiters('<p class="error">', '</p>');
			
			
			//Modelo Login
			$this->load->model('login_model', 'MLogin');
			$usuario = $this->input->post('usuario');
			$senha   = $this->input->post('senha');
			$query = $this->MLogin->validacao($usuario,$senha);
			
			if($this->form_validation->run() == FALSE){
				$this->load->view('v_login');
			}else{
				if($query){ // Verifica Login  e Senha
					$data = array(
						'usuario' =>$this->input->post('usuario'),
						'logado' => true
					);
					$this->session->set_userdate($data);
					redirect('principal');
				}else{
					redirect($this->index());
				}
			}
			
			
		}
	}

v_login.php(view)

			<?php echo form_open();?>
				<div class="body bg-gray">
					<div class="form-group" id="loginGroup">
						<?php echo form_error('usuario', '<div class="error">', '</div>'); ?>
						<div class="input-group">
							<span class="input-group-addon"><i class="fa fa-user"></i></span>
							<?php
            					echo form_input(array(
									"name" => "usuario",
									"class" => "form-control",
									"placeholder" => "Informe o Usuário"
								));
								?>						
						</div>						
					</div>
					
					<div class="form-group">
						<?php echo form_error('senha', '<div class="error">', '</div>'); ?>
						<div class="input-group" id="senhaGroup">
							<span class="input-group-addon"><i class="fa fa-lock"></i></span>
							
							<?php								
								echo form_password(array(
									"name" => "senha",
									"class" => "form-control",
									"placeholder" => "Informe a Senha"
								)); 
							?>
						</div>
					</div>					
				</div>				
				<div class="footer bg-gray">
					<?php 
						echo form_submit(array(
							"name" => "submit",
							"class" => "btn bg-orange",
							"value" => "Acessar"
						))
					?>
				</div>
			<?php form_close(); ?>