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.