Rails 2.3.8: RailsKit testing breaks with error saying there is a conflict between rails 2.3.8 and non-existant rails 3

I'm using the SASS RailsKit

   /opt/local/lib/ruby/site_ruby/1.8/rubygems.rb:283:in `activate': Unable to activate rspec-rails-2.6.1, because activesupport-2.3.8 conflicts with activesupport (~> 3.0), actionpack-2.3.8 conflicts with actionpack (~> 3.0) (Gem::LoadError)
        from /opt/local/lib/ruby/site_ruby/1.8/rubygems.rb:212:in `try_activate'
        from /opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:52:in `require'
        from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:158:in `require'
开发者_如何学编程        from ./spec/controllers/../spec_helper.rb:6
        from ./spec/controllers/accounts_controller_spec.rb:1:in `require'
        from ./spec/controllers/accounts_controller_spec.rb:1
        from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.3.2/lib/spec/runner/example_group_runner.rb:15:in `load'
        from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.3.2/lib/spec/runner/example_group_runner.rb:15:in `load_files'
        from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.3.2/lib/spec/runner/example_group_runner.rb:14:in `each'
        from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.3.2/lib/spec/runner/example_group_runner.rb:14:in `load_files'
        from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.3.2/lib/spec/runner/options.rb:134:in `run_examples'
        from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.3.2/lib/spec/runner/command_line.rb:9:in `run'
        from /opt/local/lib/ruby/gems/1.8/gems/rspec-1.3.2/bin/spec:5

My versions of things:

ruby 1.8.7 (2010-01-10 patchlevel 249) [i686-darwin10]
/opt/local/bin/ruby
gem version 1.6.0
/opt/local/bin/gem
activerecord (2.3.8)
activeresource (2.3.8)
activesupport (2.3.8)
actionmailer (2.3.8)
actionpack (2.3.8)
rails (2.3.8)
rspec-rails (2.6.1, 1.3.4)

any idea what could be cause the problem?

The best way for fix this problem it's to use RVM and dedied an gemset per application

RVM Best Pratices

rspec-rails (2.6.1) need Rails 3

gem uninstall rspec-rails