- return $this->root.DIRECTORY_SEPARATOR.substr($key, 0, 2).DIRECTORY_SEPARATOR.substr($key, 2, 2).DIRECTORY_SEPARATOR.substr($key, 4, 2).DIRECTORY_SEPARATOR.substr($key, 6);
+ return $this->root.\DIRECTORY_SEPARATOR.substr($key, 0, 2).\DIRECTORY_SEPARATOR.substr($key, 2, 2).\DIRECTORY_SEPARATOR.substr($key, 4, 2).\DIRECTORY_SEPARATOR.substr($key, 6);