Rails 3 - bundle install : ffi 0.5.4 gem error - building with native extensions

kristian-mandrups-macbook-pro:demo_app kristianconsult$ bundle install Updating git://github.com/rails/rails.git Updating git://github.com/rails/arel.git Updating git://github.com/rails/rack.git Updating git://github.com/rspec/rspec.git Updating git://github.com/negonicrac/rspec-rails.git Updating git://github.com/kristianmandrup/cucumber-rails.git Fetching source index from http://gemcutter.org Fetching source index from http://gems.github.com Resolving dependencies Installing abstract (1.0.0) from .gem files at /Users/kristianconsult/ my_rails/rails3_apps/demo_app/vendor/cache Installing actionmailer (3.0.0.beta1) from git://github.com/rails/rails.git (at master) ... Installing ffi (0.5.4) from .gem files at /Users/kristianconsult/ my_rails/rails3_apps/demo_app/vendor/cache with native extensions /usr/ local/Cellar/ruby/1.9.1-p378/lib/ruby/site_ruby/1.9.1/rubygems/ installer.rb:504:in `rescue in block in build_extensions': ERROR: Failed to build gem native extension. (Gem::Installer::ExtensionBuildError)

rake RUBYARCHDIR=/Users/kristianconsult/my_rails/rails3_apps/demo_app/ vendor/gems/ffi-0.5.4/lib RUBYLIBDIR=/Users/kristianconsult/my_rails/ rails3_apps/demo_app/vendor/gems/ffi-0.5.4/lib /usr/local/Cellar/ruby/1.9.1-p378/lib/ruby/site_ruby/1.9.1/rubygems.rb: 827:in `report_activate_error': Could not find RubyGem rake (>= 0) (Gem::LoadError)   from /usr/local/Cellar/ruby/1.9.1-p378/lib/ruby/site_ruby/1.9.1/ rubygems.rb:261:in `activate'   from /usr/local/Cellar/ruby/1.9.1-p378/lib/ruby/site_ruby/1.9.1/ rubygems.rb:68:in `gem'   from <internal:gem_prelude>:273:in `push_gem_version_on_load_path'   from <internal:gem_prelude>:14:in `gem'   from /usr/local/bin/rake:18:in `<main>'

Gem files will remain installed in /Users/kristianconsult/my_rails/ rails3_apps/demo_app/vendor/gems/ffi-0.5.4 for inspection. Results logged to /Users/kristianconsult/my_rails/rails3_apps/demo_app/ vendor/gems/ffi-0.5.4/gen/gem_make.out   from /usr/local/Cellar/ruby/1.9.1-p378/lib/ruby/site_ruby/1.9.1/ rubygems/installer.rb:507:in `block in build_extensions'   from /usr/local/Cellar/ruby/1.9.1-p378/lib/ruby/site_ruby/1.9.1/ rubygems/installer.rb:467:in `each'   from /usr/local/Cellar/ruby/1.9.1-p378/lib/ruby/site_ruby/1.9.1/ rubygems/installer.rb:467:in `build_extensions'   from /usr/local/Cellar/ruby/1.9.1-p378/lib/ruby/site_ruby/1.9.1/ rubygems/installer.rb:219:in `install'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/source.rb:127:in `install'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/installer.rb:25:in `block in run'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/installer.rb:15:in `each'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/installer.rb:15:in `run'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/installer.rb:6:in `install'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/cli.rb:54:in `install'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/vendor/thor/task.rb:32:in `run'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/vendor/thor/invocation.rb:108:in `block in invoke'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/vendor/thor/invocation.rb:115:in `call'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/vendor/thor/invocation.rb:115:in `invoke'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/vendor/thor.rb:137:in `block in start'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/vendor/thor/base.rb:369:in `start'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/lib/ bundler/vendor/thor.rb:124:in `start'   from /Users/kristianconsult/.gem/ruby/1.9.1/gems/bundler-0.9.3/bin/ bundle:4:in `<top (required)>'   from /Users/kristianconsult/.gem/ruby/1.9.1/bin/bundle:19:in `load'   from /Users/kristianconsult/.gem/ruby/1.9.1/bin/bundle:19:in `<main>'