Class 'Flow\Config' not found, in version 1.0.1

[ErFUN-KH]

I started working on version 1.0.1 with the help of my guide and I was met with this error: Class 'Flow\Config' not found

but In version 1.0.0, there was no such problem

my code:
require_once(APPPATH.'third_party'."/Flow/autoloader.php");
$config = new \Flow\Config();
.
.
.