Fatal error: Uncaught Error: Class "Symfony\Component\Form\AbstractExtension" not found in I:\www\frameworks\Symfony\doctrine\vendor\symfony\form\Extension\Csrf\CsrfExtension.php:23 Stack trace: #0 {main} thrown in I:\www\frameworks\Symfony\doctrine\vendor\symfony\form\Extension\Csrf\CsrfExtension.php on line 23