Fatal error: Uncaught Error: Class "Symfony\Component\Validator\Mapping\Loader\LoaderChain" not found in I:\www\frameworks\Symfony\doctrine\vendor\symfony\validator\Mapping\Loader\FilesLoader.php:23 Stack trace: #0 {main} thrown in I:\www\frameworks\Symfony\doctrine\vendor\symfony\validator\Mapping\Loader\FilesLoader.php on line 23