FAILURE: Build failed with an exception.

* Where:
Build file '/home/anderson/installs/google/gae/gaelyk/projects/i2m2-test/build.gradle' line: 3

* What went wrong:
A problem occurred evaluating root project 'i2m2-test'.
Cause: Could not generate a proxy class for class eu.appsatori.gradle.fatjar.tasks.PrepareFiles.

* Try:
Run with -d option to get more details. Run with -S option to get the full (very verbose) stacktrace.

* Exception is:
org.gradle.api.LocationAwareGradleScriptException: Build file '/home/anderson/installs/google/gae/gaelyk/projects/i2m2-test/build.gradle' line: 3
A problem occurred evaluating root project 'i2m2-test'.
    at org.gradle.groovy.scripts.DefaultScriptRunnerFactory$ScriptRunnerImpl.run(DefaultScriptRunnerFactory.java:51)
    at org.gradle.configuration.DefaultScriptPluginFactory$ScriptPluginImpl.apply(DefaultScriptPluginFactory.java:127)
    at org.gradle.configuration.BuildScriptProcessor.evaluate(BuildScriptProcessor.java:38)
    at org.gradle.configuration.DefaultProjectEvaluator.evaluate(DefaultProjectEvaluator.java:38)
    at org.gradle.api.internal.project.AbstractProject.evaluate(AbstractProject.java:506)
    at org.gradle.api.internal.project.AbstractProject.evaluate(AbstractProject.java:71)
    at org.gradle.configuration.ProjectEvaluationConfigurer.execute(ProjectEvaluationConfigurer.java:23)
    at org.gradle.configuration.ProjectEvaluationConfigurer.execute(ProjectEvaluationConfigurer.java:21)
    at org.gradle.configuration.DefaultBuildConfigurer$1.execute(DefaultBuildConfigurer.java:38)
    at org.gradle.configuration.DefaultBuildConfigurer$1.execute(DefaultBuildConfigurer.java:35)
    at org.gradle.api.internal.project.AbstractProject.configure(AbstractProject.java:482)
    at org.gradle.api.internal.project.AbstractProject.allprojects(AbstractProject.java:477)
    at org.gradle.configuration.DefaultBuildConfigurer.configure(DefaultBuildConfigurer.java:35)
    at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:136)
    at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:107)
    at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:75)
    at org.gradle.launcher.RunBuildAction.execute(RunBuildAction.java:41)
    at org.gradle.launcher.RunBuildAction.execute(RunBuildAction.java:27)
    at org.gradle.launcher.CommandLineActionFactory$WithLoggingAction.execute(CommandLineActionFactory.java:209)
    at org.gradle.launcher.CommandLineActionFactory$WithLoggingAction.execute(CommandLineActionFactory.java:193)
    at org.gradle.launcher.Main.execute(Main.java:55)
    at org.gradle.launcher.Main.main(Main.java:40)
    at org.gradle.launcher.ProcessBootstrap.runNoExit(ProcessBootstrap.java:46)
    at org.gradle.launcher.ProcessBootstrap.run(ProcessBootstrap.java:28)
    at org.gradle.launcher.GradleMain.main(GradleMain.java:24)
    at org.gradle.wrapper.BootstrapMainStarter.start(BootstrapMainStarter.java:37)
    at org.gradle.wrapper.Wrapper.execute(Wrapper.java:64)
    at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:42)
Caused by: org.gradle.api.GradleException: Could not generate a proxy class for class eu.appsatori.gradle.fatjar.tasks.PrepareFiles.
    at org.gradle.api.internal.AbstractClassGenerator.generate(AbstractClassGenerator.java:131)
    at org.gradle.api.internal.project.taskfactory.TaskFactory.createTaskObject(TaskFactory.java:86)
    at org.gradle.api.internal.project.taskfactory.TaskFactory.createTask(TaskFactory.java:55)
    at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory.createTask(AnnotationProcessingTaskFactory.java:66)
    at org.gradle.api.internal.project.taskfactory.DependencyAutoWireTaskFactory.createTask(DependencyAutoWireTaskFactory.java:39)
    at org.gradle.api.internal.tasks.DefaultTaskContainer.add(DefaultTaskContainer.java:46)
    at org.gradle.api.internal.tasks.DefaultTaskContainer.add(DefaultTaskContainer.java:64)
    at org.gradle.api.tasks.TaskContainer$add.call(Unknown Source)
    at eu.appsatori.gradle.fatjar.FatJarPlugin.apply(FatJarPlugin.groovy:55)
    at eu.appsatori.gradle.fatjar.FatJarPlugin.apply(FatJarPlugin.groovy)
    at org.gradle.api.internal.plugins.DefaultProjectsPluginContainer.providePlugin(DefaultProjectsPluginContainer.java:103)
    at org.gradle.api.internal.plugins.DefaultProjectsPluginContainer.addPluginInternal(DefaultProjectsPluginContainer.java:67)
    at org.gradle.api.internal.plugins.DefaultProjectsPluginContainer.apply(DefaultProjectsPluginContainer.java:37)
    at org.gradle.api.plugins.gae.GaePlugin.applyFatJarPlugin(GaePlugin.groovy:128)
    at org.gradle.api.plugins.gae.GaePlugin.this$2$applyFatJarPlugin(GaePlugin.groovy)
    at org.gradle.api.plugins.gae.GaePlugin$this$2$applyFatJarPlugin.callCurrent(Unknown Source)
    at org.gradle.api.plugins.gae.GaePlugin.apply(GaePlugin.groovy:83)
    at org.gradle.api.plugins.gae.GaePlugin.apply(GaePlugin.groovy)
    at org.gradle.api.internal.plugins.DefaultProjectsPluginContainer.providePlugin(DefaultProjectsPluginContainer.java:103)
    at org.gradle.api.internal.plugins.DefaultProjectsPluginContainer.addPluginInternal(DefaultProjectsPluginContainer.java:67)
    at org.gradle.api.internal.plugins.DefaultProjectsPluginContainer.apply(DefaultProjectsPluginContainer.java:37)
    at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction.applyPlugin(DefaultObjectConfigurationAction.java:101)
    at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction.access$200(DefaultObjectConfigurationAction.java:32)
    at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction$3.run(DefaultObjectConfigurationAction.java:72)
    at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction.execute(DefaultObjectConfigurationAction.java:114)
    at org.gradle.api.internal.project.AbstractProject.apply(AbstractProject.java:873)
    at org.gradle.api.Project$apply.call(Unknown Source)
    at org.gradle.api.internal.project.ProjectScript.apply(ProjectScript.groovy:35)
    at org.gradle.api.Script$apply.callCurrent(Unknown Source)
    at build_gradle_272bdddfdd63af314871b68e21253395.run(/home/anderson/installs/google/gae/gaelyk/projects/i2m2-test/build.gradle:3)
    at org.gradle.groovy.scripts.DefaultScriptRunnerFactory$ScriptRunnerImpl.run(DefaultScriptRunnerFactory.java:49)
    ... 27 more
Caused by: java.lang.NoClassDefFoundError: org/gradle/api/internal/tasks/execution/TaskValidator
    at org.gradle.api.internal.AbstractClassGenerator.generate(AbstractClassGenerator.java:88)
    ... 57 more
Caused by: java.lang.ClassNotFoundException: org.gradle.api.internal.tasks.execution.TaskValidator
    ... 58 more