[SYmfony 2.8] Erreur lors du lancement de l'application

Bonjour,

Je viens de réinstaller un vieux projet php sous Symfony 2.8 et lors du lancement de l'application sous chrome, j'obtiens une erreur :

RuntimeException in TreeBuilder.php line 55:
The configuration tree has no root node.

in TreeBuilder.php line 55
at TreeBuilder->buildTree() in Processor.php line 50
at Processor->processConfiguration(object(Configuration), array(array())) in Extension.php line 99
at Extension->processConfiguration(object(Configuration), array(array())) in StanhomeMeetingExtension.php line 23
at StanhomeMeetingExtension->load(array(array()), object(ContainerBuilder)) in MergeExtensionConfigurationPass.php line 55
at MergeExtensionConfigurationPass->process(object(ContainerBuilder)) in MergeExtensionConfigurationPass.php line 39
at MergeExtensionConfigurationPass->process(object(ContainerBuilder)) in Compiler.php line 104
at Compiler->compile(object(ContainerBuilder)) in ContainerBuilder.php line 597
at ContainerBuilder->compile() in bootstrap.php.cache line 2725
at Kernel->initializeContainer() in bootstrap.php.cache line 2503
at Kernel->boot() in app_dev.php line 26

Le fichier StanhomeMeetingExtension qui semble avoir un soucis à la ligne 23 :

<?php

namespace Stanhome\MeetingBundle\DependencyInjection;

use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\Config\FileLocator;
use Symfony\Component\HttpKernel\DependencyInjection\Extension;
use Symfony\Component\DependencyInjection\Loader;

/**
 * This is the class that loads and manages your bundle configuration
 *
 * To learn more see {@link http://symfony.com/doc/current/cookbook/bundles/extension.html}
 */
class StanhomeMeetingExtension extends Extension
{
    /**
     * {@inheritdoc}
     */
    public function load(array $configs, ContainerBuilder $container)
    {
        $configuration = new Configuration();
        $config = $this->processConfiguration($configuration, $configs);

        $loader = new Loader\YamlFileLoader($container, new FileLocator(__DIR__.'/../Resources/config'));
        $loader->load('services.yml');
    }
}

Je ne comprends pas ce genre d'erreur. Des idées ?
La base de données est présente en local.
Je ne peux pas lancer de commandes, j'ai le message d'erreur qui s'affiche également.

Merci