Cloudbees：App Engine部署失败

从Cloudbees DEV @ cloud Jenkins实例部署到GAE时出现奇怪的错误：

[cloudbees-deployer] Deploying as [email protected] to Google App Engine
[cloudbees-deployer] Deploying PROJECTNAME
[cloudbees-deployer]   Resolved from workspace as /scratch/jenkins/workspace/PROJECTNAME/PROJECTNAME
ERROR: Couldn't find path for tool 'GAE Python SDK 1.7 (latest)' 
com.cloudbees.plugins.deployer.exceptions.DeployException: No {0} SDK available for node.
    at com.cloudbees.plugins.deployer.impl.google.PythonEngineImpl$DeployActorImpl.<init>(PythonEngineImpl.java:224)
    at com.cloudbees.plugins.deployer.impl.google.PythonEngineImpl.newDeployActor(PythonEngineImpl.java:62)
    at com.cloudbees.plugins.deployer.impl.google.PythonEngineImpl.newDeployActor(PythonEngineImpl.java:44)
    at com.cloudbees.plugins.deployer.engines.Engine.process(Engine.java:159)
    at com.cloudbees.plugins.deployer.engines.Engine.perform(Engine.java:100)
    at com.cloudbees.plugins.deployer.DeployBuilder.perform(DeployBuilder.java:85)
    at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
    at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:791)
    at hudson.model.Build$BuildExecution.build(Build.java:199)
    at hudson.model.Build$BuildExecution.doRun(Build.java:160)
    at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:572)
    at hudson.model.Run.execute(Run.java:1665)
    at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
    at hudson.model.ResourceController.execute(ResourceController.java:88)
    at hudson.model.Executor.run(Executor.java:246)
Build step 'Deploy applications' marked build as failure
Recording test results

现在，这曾经起作用。我将节点安装作为测试脚本的一部分，因此Jenkins可以使用casperjs和phantom运行测试套件。但是，该应用程序本身不使用节点（在Google App Engine中为Python）。两条相关的线似乎是

ERROR: Couldn't find path for tool 'GAE Python SDK 1.7 (latest)' 
com.cloudbees.plugins.deployer.exceptions.DeployException: No {0} SDK available for node.

而且我不明白在寻找什么路径，或者为什么节点需要一个SDK。（我认为那里的“节点”并不意味着“ nodejs”；我的意思是“ Jenkins在其上运行的该节点；即一台计算机”。）

那么，为什么部署者找不到SDK？更重要的是，我该如何解决？