protected function evalSkin($value, $name)
    {
        $result = isset($this->skinConfiguration[$value]) &&
            class_exists($this->skinConfiguration[$value][static::SKIN_CLASS]) &&
            $this->pool->fileService->fileIsReadable(
                $this->skinConfiguration[$value][static::SKIN_DIRECTORY] . 'header.html'
            );

        if ($result === false) {
            $this->pool->messages->addMessage(static::KEY_CONFIG_ERROR . ucfirst($name));
        }

        return $result;
    }