Attempting to limit access with Administrators module

I have a Trixbox 2.2. I want to setup a user so they can make certian changes but not have access to anything else.

I followed the help instructions at
http://www.freepbx.org/freepbx-help-system?freepbx_version=2.3.1.3&freepbx_menuitem=ampusers
To setup Trixbox so I can add an administrator in freepbx. But when every I try to login it fails. I get a 404 not found page.

Is there something I’m missing?
To login as another user go you just login like this: http://IPaddress/{username} ?