Problem with tank_auth and fuel users

Hello,

I have a site where I implemented tank_auth.

I have a controller called auth.
A folder in the models folder called: tank_auth with a users.php file in it.

The problem is now, when I try to go to users in the admin tools, I get these errors:

Undefined property: Users::$form
Filename: fuel/Loader.php
Line Number: 215

Undefined property: Users::$fuel_auth
Filename: libraries/Fuel_base_controller.php
Line Number: 31

Fatal error: Call to a member function user_data() on a non-object in C:\wamp\www\highlandfuel\fuel\modules\fuel\libraries\Fuel_base_controller.php on line 31
Call Stack
# Time Memory Function Location
1 0.0012 397568 {main}( ) ..\index.php:0
2 0.0035 461632 require_once( 'C:\wamp\www\highlandfuel\fuel\codeigniter\core\CodeIgniter.php' ) ..\index.php:236
3 0.0511 2229680 Users->__construct( ) ..\CodeIgniter.php:267
4 0.0511 2229680 Module->__construct( ) ..\users.php:10
5 0.0511 2229680 Fuel_base_controller->__construct( ) ..\module.php:13
6 0.0511 2229712 CI_Controller->__construct( ) ..\Fuel_base_controller.php:13
7 0.0606 2838056 CI_Loader->_ci_autoloader( ) ..\Controller.php:53
8 0.0977 4315496 Fuel_Loader->library( ) ..\Loader.php:1033
9 0.0981 4316392 Fuel_Loader->_ci_load_class( ) ..\Loader.php:205
10 0.1021 4589152 CI_Loader->_ci_init_class( ) ..\Loader.php:436
11 0.1029 4594376 Tank_auth->__construct( ) ..\Loader.php:956
12 0.1216 5620048 Fuel_Loader->model( ) ..\tank_auth.php:31
13 0.1336 6406264 Users->__construct( ) ..\Loader.php:240
14 0.1336 6406264 Module->__construct( ) ..\users.php:10
15 0.1336 6406264 Fuel_base_controller->__construct( ) ..\module.php:13

When I change the tank_auth/users.php model file to a different name and try to go to users in the admin, I get this error: Unable to locate the file: tank_auth/users.php

Why does the admin url (localhost/mysite/fuel/users) tries to go to tank_auth?

How can I fix this?

Thanks,

Sigal