ActiveAdmin issue

gistfile1.txt

Started GET "/admin/admin_users" for 192.168.0.100 at 2012-11-27 19:17:31 +0530
Processing by Admin::AdminUsersController#index as HTML
FB auth token is 
device token is 
  AdminUser Load (1.7ms)  SELECT "admin_users".* FROM "admin_users" WHERE "admin_users"."id" = 1 LIMIT 1
   (1.7ms)  SELECT COUNT(count_column) FROM (SELECT 1 AS count_column FROM "admin_users" LIMIT 30 OFFSET 0) subquery_for_count 
   (1.0ms)  SELECT COUNT(*) FROM "admin_users" 
  CACHE (0.0ms)  SELECT COUNT(count_column) FROM (SELECT 1 AS count_column FROM "admin_users" LIMIT 30 OFFSET 0) subquery_for_count 
  AdminUser Load (1.6ms)  SELECT "admin_users".* FROM "admin_users" ORDER BY "admin_users"."id" desc LIMIT 30 OFFSET 0
  Rendered /home/krishna/.rvm/gems/ruby-1.9.3-p194@ferrotec-trail/gems/activeadmin-0.5.0/app/views/active_admin/resource/index.html.arb (932.2ms)
Completed 500 Internal Server Error in 1289ms

ActionView::Template::Error (I don't know what to do with NilClass params: nil):
    1: insert_tag renderer_for(:index)
  activeadmin (0.5.0) lib/active_admin/view_helpers/fields_for.rb:38:in `block in fields_for_params'
  activeadmin (0.5.0) lib/active_admin/view_helpers/fields_for.rb:20:in `each'
  activeadmin (0.5.0) lib/active_admin/view_helpers/fields_for.rb:20:in `map'
  activeadmin (0.5.0) lib/active_admin/view_helpers/fields_for.rb:20:in `fields_for_params'
  activeadmin (0.5.0) lib/active_admin/view_helpers/form_helper.rb:12:in `hidden_field_tags_for'
  activeadmin (0.5.0) lib/active_admin/filters/forms.rb:83:in `block (2 levels) in active_admin_filters_form_for'
  actionpack (3.2.3) lib/action_view/helpers/capture_helper.rb:40:in `block in capture'
  actionpack (3.2.3) lib/action_view/helpers/capture_helper.rb:187:in `with_output_buffer'
  haml (3.1.7) lib/haml/helpers/xss_mods.rb:109:in `with_output_buffer_with_haml_xss'

Did you have any luck with this?