For Rails 4+

If you are running Rails 4+ use f.actions instead of f.buttons. Here's an issue that talks about this change on the ActiveAdmin repo https://github.com/activeadmin/activeadmin/issues/1085

Original answer for OP question in 2012

seems like formtastic 2.2.0 (released today) breaks active_admin and since active_admin requires formtastic >= 2.0.0... put in your Gemfile this

gem "formtastic", "~> 2.1.1"gem "activeadmin", "~> 0.4.3"

then run

bundle update formtastic

then restart your server (if you have it running)..

and should work ok...

I had same problem and it's killed my about hours.

I am using rails 4 and active admin form master git:

gem 'activeadmin', github: 'gregbell/active_admin'

I just used "f.actions" instead of "f.buttons"

form do |f|  f.inputs "Enter Todo details" do    f.input :quote_id, :as => :select, :collection => Quote.all.map {|q| [ q.contact,q.id]}, :include_blank => false     f.input :name, :label => "Name of customer"    f.input :state, :as => :select, :collection => ['Active','Closed'], :include_blank => false    f.input :moving_date    f.input :revisit    f.input :address    f.input :status  end  f.actionsend

It's works for me.

I have done following changes in the gemfile

gem 'activeadmin', '0.4.2'gem 'formtastic', '2.0.0'

and it solved the same issue.reason is same as explained above .the formtastic 2.2.0 is incompatible with activeadmin current version