Unable to load the requested class

[eluser]briang[/eluser]
In my application/libraries/ directory...

I am trying to extend my "MY_Controller" class with a "MY_Auth" class.

The MY_Controller class I have already created works great. But when I create any other classes I continually get this error:

An Error Was Encountered
Unable to load the requested class: Auth

The steps I am taking:

1) I create the file named MY_Auth.php, save it to 'application/libraries/'
2) Its code:

Code:

class MY_Auth extends Controller{
function __construct(){
  parent::__construct();
}
}

3) Open the config/autoload.php and change this line to contain my new class:

Code:

$autoload['libraries'] = array('database','auth');

Then get the error. I don't understand how to get past this.

Also, why did I not have to add MY_Controller to the $autoload[] array? And it works just fine. I have tried not adding MY_Auth, but then it errors out as well.

Please help.
Thank you.
Brian