Missing type intptr_t from ffi

irb(main):001:0> require 'rubygems'
=> true
irb(main):002:0> require 'capybara'
=> true
irb(main):003:0> require 'capybara/dsl'
=> true
irb(main):004:0> Capybara.run_server = false
=> false
irb(main):005:0> Capybara.current_driver = :selenium
=> :selenium
irb(main):007:0> include Capybara::DSL
=> Object
irb(main):008:0> visit 'http://google.com'
TypeError: unable to resolve type 'intptr_t'
        from f:/dev/jruby-1.6.6/lib/ruby/site_ruby/shared/ffi/types.rb:56:in `find_type'
        from f:/dev/jruby-1.6.6/lib/ruby/site_ruby/shared/ffi/library.rb:329:in `find_type'
        from f:/dev/jruby-1.6.6/lib/ruby/site_ruby/shared/ffi/library.rb:158:in `attach_function'
        from org/jruby/RubyArray.java:1614:in `each'
        from f:/dev/jruby-1.6.6/lib/ruby/site_ruby/shared/ffi/library.rb:150:in `attach_function'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/childprocess-0.3.1/lib/childprocess/windows/lib.rb:146:in `Lib'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/childprocess-0.3.1/lib/childprocess/windows/lib.rb:29:in `Windows'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/childprocess-0.3.1/lib/childprocess/windows/lib.rb:2:in `ChildProcess'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/childprocess-0.3.1/lib/childprocess/windows/lib.rb:1:in `(root)'
        from org/jruby/RubyKernel.java:1027:in `require'
        from f:/dev/jruby-1.6.6/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/childprocess-0.3.1/lib/childprocess/windows/lib.rb:28:in `(root)'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/childprocess-0.3.1/lib/childprocess/windows.rb:23:in `new'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/selenium-webdriver-2.18.0/lib/selenium/webdriver/firefox/binary.rb:50:in `execute'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/selenium-webdriver-2.18.0/lib/selenium/webdriver/firefox/binary.rb:30:in `start_with'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/selenium-webdriver-2.18.0/lib/selenium/webdriver/firefox/launcher.rb:68:in `start_silent_and_wait'
... 6 levels...
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/capybara-1.1.2/lib/capybara/selenium/driver.rb:15:in `browser'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/capybara-1.1.2/lib/capybara/selenium/driver.rb:36:in `visit'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/capybara-1.1.2/lib/capybara/session.rb:157:in `visit'
        from f:/dev/jruby-1.6.6/lib/ruby/gems/1.8/gems/capybara-1.1.2/lib/capybara/dsl.rb:165:in `visit'
        from (irb):8:in `evaluate'
        from org/jruby/RubyKernel.java:1077:in `eval'
        from f:/dev/jruby-1.6.6/lib/ruby/1.8/irb.rb:158:in `eval_input'
        from f:/dev/jruby-1.6.6/lib/ruby/1.8/irb.rb:271:in `signal_status'
        from f:/dev/jruby-1.6.6/lib/ruby/1.8/irb.rb:155:in `eval_input'
        from org/jruby/RubyKernel.java:1408:in `loop'
        from org/jruby/RubyKernel.java:1181:in `catch'
        from f:/dev/jruby-1.6.6/lib/ruby/1.8/irb.rb:154:in `eval_input'
        from f:/dev/jruby-1.6.6/lib/ruby/1.8/irb.rb:71:in `start'
        from org/jruby/RubyKernel.java:1181:in `catch'
        from f:/dev/jruby-1.6.6/lib/ruby/1.8/irb.rb:70:in `start'