Testing Problems

I am following this tutorial http://www.aidanf.net/rails_user_authentication_tutorial
to create a basic user auth system, but when I try and run the test I
get a slew of errors with rails:

d:/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:196:in `activate': can't
activate rai
ls (= 1.2.2), already activated rails-1.2.1] (Gem::Exception)
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:
32:in `re
quire'
        from d:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.0/lib/
active_suppo
rt/dependencies.rb:496:in `require'
        from d:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.0/lib/
active_suppo
rt/dependencies.rb:343:in `new_constants_in'
        from d:/ruby/lib/ruby/gems/1.8/gems/activesupport-1.4.0/lib/
active_suppo
rt/dependencies.rb:496:in `require'
        from ./test/unit/../test_helper.rb:3
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:
27:in `ge
m_original_require'
        from d:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:
27:in `re
quire'
        from test/unit/user_test.rb:1

This is my first go a TDD, any help would be appreciated.