Got this when running bundler after upgrading to Bamboo 5.
Starting task 'Bundler' of type 'au.id.wolfe.bamboo.rake-bamboo-plugin:task.builder.bundler'
error 15-Jul-2013 12:36:01 Error occurred while running Task '(2)' of type au.id.wolfe.bamboo.rake-bamboo-plugin:task.builder.bundler.
error 15-Jul-2013 12:36:01 java.lang.IncompatibleClassChangeError: Found interface com.atlassian.utils.process.ExternalProcess, but class was expected
error 15-Jul-2013 12:36:01 at au.id.wolfe.bamboo.ruby.tasks.AbstractRubyTask.execute(AbstractRubyTask.java:66)
error 15-Jul-2013 12:36:01 at com.atlassian.bamboo.task.TaskExecutorImpl.executeTasks(TaskExecutorImpl.java:208)
error 15-Jul-2013 12:36:01 at com.atlassian.bamboo.task.TaskExecutorImpl.execute(TaskExecutorImpl.java:98)
error 15-Jul-2013 12:36:01 at com.atlassian.bamboo.build.pipeline.tasks.ExecuteBuildTask.call(ExecuteBuildTask.java:75)
error 15-Jul-2013 12:36:01 at com.atlassian.bamboo.v2.build.agent.DefaultBuildAgent.build(DefaultBuildAgent.java:188)
error 15-Jul-2013 12:36:01 at com.atlassian.bamboo.v2.build.agent.BuildAgentControllerImpl.waitAndPerformBuild(BuildAgentControllerImpl.java:102)
error 15-Jul-2013 12:36:01 at com.atlassian.bamboo.v2.build.agent.DefaultBuildAgent$1.run(DefaultBuildAgent.java:107)
error 15-Jul-2013 12:36:01 at com.atlassian.bamboo.build.pipeline.concurrent.NamedThreadFactory$2.run(NamedThreadFactory.java:52)
error 15-Jul-2013 12:36:01 at java.lang.Thread.run(Thread.java:680)
Got this when running bundler after upgrading to Bamboo 5.