Constantes

Srs, bom dia!

Eu criei uma classe para controle das constantes. É impresso um erro nesta classe eu sei exatamente onde está o ponto do erro, mas não sei o porque e como resolve-lo. Se alguém conseguir ajudar eu agradeço.

class Constants
  {
    const DEBUG = false;

      public function __construct()
      {
        define('DRIVE', 'mysql');
        define('HOST', 'localhost');
      define('DB_NAME', 'voxus' );
      define('USER', 'root');
      define('PASSWORD', 'xura123@');
      define('DEBUG', false);
      }

      public function getDrive()
      {
        return DRIVE;    
      }

      public function getHost()
      {
        return HOST;    
      }

      public function getDBName()
      {
        return DB_NAME;    
      }

      public function getUser()
      {
        return USER;    
      }

      public function getPassword()
      {
        return PASSWORD;    
      }

      public static function getDebug()
      {
        return self::DEBUG;    
      }
  }

<?php   
  require_once("Constants.php");

  class Connection
  { 
    public static function connect()
    {      
      $constant = new Constants();

      $connection = new PDO($constant->getDrive().
                            ':host='.$constant->getHost().
                            ';dbname='.$constant->getDBName(), 
                            $constant->getUser(), 
                            $constant->getPassword());
      return $connection;
    }
  }

?php 
  require_once('../../classes/importClasses.php');
  require_once('../../model/task/database.php');

  try{ 
    $factory = new TaskFactory();
    $task = $factory->create($_POST);  

    if($_FILES['file']['tmp_name']):
      $extent = strtolower(substr($_FILES['file']['name'], -4));
      $file_name = md5(time()).$extent;
      $directory = "c:/xampp/htdocs/voxus/views/files/";
      move_uploaded_file($_FILES['file']['tmp_name'], $directory.$file_name);
      $task->setFile($directory.$file_name);        
    endif;  

    $task->setCode(createCode());                   
    insert($task); //<-*****************************   

    header('Location:../../views/tasks.php');
    die();

  }catch(Exception $e){      
    Insure::takeCare($e);
  }

function connection()
  {
    $connection = Connection::connect();
    return $connection;
  }

function insert(Task $task)
  {
    Insure::checkData($task->getName());
    Insure::checkData($task->getDescription());

    $query = "INSERT INTO tasks(code, name, description, file) 
              VALUES(:code, :name, :description, :file)";    

    $stmt = connection()->prepare($query);  <- ERRO ACONTECE NESTE TRECHO 
    $stmt->bindValue(':code', $task->getCode());
    $stmt->bindValue(':name', $task->getName());
    $stmt->bindValue(':description', $task->getDescription());
    $stmt->bindValue(':file', $task->getFile());
    $stmt->execute();
  }