確かに『SamplePageController.php』をサーバーから削除するとEC-CUBEが動きます。namespaceは『namespace　Customize\Controller;』となっていますがどこが間違っているのかがわかりません＞＜；

【SamplePageController.phの記述】
namespace Customize\Controller;

use Eccube\Controller\AbstractController;
use Eccube\Entity\BaseInfo;
use Eccube\Entity\Product;
use Eccube\Repository\BaseInfoRepository;
use Eccube\Repository\ProductRepository;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
use Symfony\Component\Routing\Annotation\Route;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Template;

class SamplePageController extends AbstractController
{
/** @var BaseInfo */
protected $baseInfo;

/** @var Product */
protected $productRepository;

/**
* SamplePageController constructor.
* @param BaseInfoRepository $baseInfoRepository
* @param ProductRepository $productRepository
*/
public function __construct(
BaseInfoRepository $baseInfoRepository,
ProductRepository $productRepository
)
{
$this->baseInfo = $baseInfoRepository->get();
$this->productRepository = $productRepository;
}

/**
* @Route("/sample/{id}", name="sample_index")
* @Template("Sample/index.twig")
*/
public function index($id)
{
// $product = $this->entityManager->getRepository('Eccube\Entity\Product')->find($id);
$product = $this->productRepository->find($id);

return [
'shop_name' => $this->baseInfo->getShopName(),
'maker_name' => $product->getMakerName(),
'product_name' => $product->getName(),
];
}
}