Running cap bootstrap on JRUBY results in NotImplementedError: fork is not available on this platform

[henry74]

When it gets to this particular part of the bootstrap process the following error occurs:

  * 2014-03-19 10:31:02 executing `bootstrap:user'
NotImplementedError: fork is not available on this platform
                                 fork at org/jruby/RubyKernel.java:1884
                             do_popen at /home/SopranoAPI/vendor/jruby/1.9/gems/open4-1.3.1/lib/open4.rb:62
                               popen4 at /home/SopranoAPI/vendor/jruby/1.9/gems/open4-1.3.1/lib/open4.rb:34
                              execute at /home/SopranoAPI/vendor/jruby/1.9/gems/recap-1.2.2/lib/recap/support/shell_command.rb:8
                                 each at org/jruby/RubyArray.java:1613
                              execute at /home/SopranoAPI/vendor/jruby/1.9/gems/recap-1.2.2/lib/recap/support/shell_command.rb:7
                            Bootstrap at /home/SopranoAPI/vendor/jruby/1.9/gems/recap-1.2.2/lib/recap/tasks/bootstrap.rb:63
                        instance_eval at org/jruby/RubyBasicObject.java:1536
                 invoke_task_directly at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/configuration/execution.rb:138
  invoke_task_directly_with_callbacks at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/configuration/callbacks.rb:25
                         execute_task at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/configuration/execution.rb:89
                       method_missing at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/configuration/namespaces.rb:191
                                 user at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/configuration/namespaces.rb:110
                            Bootstrap at /home/SopranoAPI/vendor/jruby/1.9/gems/recap-1.2.2/lib/recap/tasks/bootstrap.rb:78
                        instance_eval at org/jruby/RubyBasicObject.java:1536
                 invoke_task_directly at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/configuration/execution.rb:138
  invoke_task_directly_with_callbacks at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/configuration/callbacks.rb:25
                         execute_task at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/configuration/execution.rb:89
                find_and_execute_task at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/configuration/execution.rb:101
            execute_requested_actions at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/cli/execute.rb:46
                                 each at org/jruby/RubyArray.java:1613
            execute_requested_actions at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/cli/execute.rb:45
  execute_requested_actions_with_help at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/cli/help.rb:19
                             execute! at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/cli/execute.rb:34
                              execute at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/lib/capistrano/cli/execute.rb:14
                               (root) at /home/SopranoAPI/vendor/jruby/1.9/gems/capistrano-2.15.5/bin/cap:4
                                 load at org/jruby/RubyKernel.java:1101
                               (root) at /home/SopranoAPI/vendor/jruby/1.9/bin/cap:23