Duplicate beta4: creating user from admin panel results in error

[User]

Reproducable.

Go to /admin.php?users/add
Enter a user, the user name validation will thrown an error. The error message on screen simply says:
The following error occurred

The server responded with an error. The error message is in the JavaScript console.
Here's the error message from Firebug:
Fatal error: Call to undefined method XenForo_ControllerAdmin_User::_getFieldNameForValidation() in /home/*****/public_html/community/library/XenForo/ControllerAdmin/User.php on line 389
The Firebug console screenshot attached.

 

[Andy.N]

duplicate?
http://xenforo.com/community/threads/error-at-creation-of-the-user-in-1-1b4.22275/

 

[User]

FML
Searched and didn't come across the above thread. Yeah it's the same problem.