I'm trying to use Active Merchant with a new Rails 3.1.3 app and I'm getting the following error:
rails plugin install git://github.com/Shopify/active_merchant.git
rails server
=> Booting WEBrick
=> Rails 3.1.3 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/.rvm/gems/ruby-1.9.2-p290@rails3.1/gems/activesupport-3.1.3/lib/active_support/dependencies.rb:240:in `require': no such file to load -- active_utils (LoadError)
Got the same issue and it turn out to be adding gem 'active_utils' in your gem file.
Hope so this will solve your problem. Thanks