Doesn't work as extension install in radiant 0.9.1

[cmyk]

I installed it being in the root dir of the radiant project:
script/extension install rbac_base

I got this error:

Showing /usr/local/lib/ruby/gems/1.8/gems/radiant-0.9.1/app/views/admin/users/index.html.haml where line #26 raised:

23:                 = link_to user.name, edit_admin_user_url(user)
24:                 %span.login= h user.login
25:             - tbody.roles_cell do
26:               %td.roles= roles(user)
27:             - tbody.modify_cell do
28:               %td.remove
29:                 - if user == current_user