uninitialized constant error with restful authentication

I'm trying to set up restful authentication with Rails 2.1.0 on Mac OS X Leopard, and I had to comment out RAILS_GEM_VERSION in the environment file to install the plugin from technoweenie. Now I'm trying to follow along in a tuturial, and I'm stuck on this:

   1. $ ruby script/generate scaffold Role rolename:string    2. /Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:492:in `const_missing': uninitialized constant User::Authentication (NameError)    3. from /Users/naijaguy/Sites/rails_apps/testauthapp/app/models/user.rb:4    4. from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:215:in `load_without_new_constant_marking'    5. from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:215:in `load_file'    6. from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:354:in `new_constants_in'    7. from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:214:in `load_file'    8. from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:95:in `require_or_load'    9. from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:260:in `load_missing_constant'   10. from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.0/lib/active_support/dependencies.rb:467:in `const_missing'   11. ... 28 levels...   12. from /Library/Ruby/Gems/1.8/gems/rails-2.1.0/lib/commands/generate.rb:1   13. from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `gem_original_require'   14. from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `require'   15. from script/generate:3

Was something (e.g. Authentication) not included when I downloaded the plugin? I added this line to my ApplicationController:

include AuthenticatedSystem