Fatal error: Cannot redeclare class Cake\View\Helper

Hello, I would like to get a hint, where to start with this error.

Fatal error: Cannot redeclare class Cake\View\Helper\ViewToolsHelper in F:\xampp\htdocs\eulehours\src\View\Helper\ViewToolsHelper.php on line 46

The below code is found in a helper file: ViewToolsHelper.php.
In the file AppView.php I have included the load:

public function initialize()
{
$this->loadHelper('ViewTools');
}

It works fine but everytime I call from the default.ctp a link:

        <li><?= $this->Html->link(__('Data Reset'), ['controller' => 'hours', 'action' => 'resethours']); ?></li> 

I get the error shown as subject. Other action calls like the ‘index’ are working fine.
I have a template file resethours.ctp:

Ergebnis der Aktion

$this->Flash->success(__('Daten bearbeitet!'));

============================================
use Cake\View\Helper;
use UnexpectedValueException;
use Cake\Core\Configure;
use Cake\Core\Configure\Engine\PhpConfig;
/**
*/
class ViewToolsHelper extends Helper
{

  protected $names = [];
/**
 */
public function getallparameter($kind, $key )
{
if($kind=='P') {
$appMeters = Configure::read('Parameter');    
$names[0] = substr($appMeters[$key],0 ,strpos($appMeters[$key], '|' ));
$names[1] = substr(strrchr($appMeters[$key], '|' ),1);
$names[2] = $appMeters['relHours'];
$names[3] = $appMeters['relReports'];
}
    return $names;
}

}

?>

I believe you forgot to add the namespace to beginning of your helper:

namespace App\View\Helper;