GWT设计器部署错误

我正在尝试部署我的第一个GWT应用程序，但是我得到了下面的错误。 我正在使用jre6、GWT Designer（使用GWT DSK 2.5.0），并且我已经删除了GWT unitCache文件夹，如下所示：

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你用的是什么版本的Eclipse？我用的是Juno。我创建了一个Ant build.xml文件作为解决方法，它工作正常。

Designer error occurred. 
Select Details >> for more information. 
See the Error Log for more information.
Reason: Parse error or internal Designer error.
Plug-in Provider: Google
Plug-in Name: 
Plug-in ID: org.eclipse

java.lang.NoClassDefFoundError: org/eclipse/jdt/launching/IJavaLaunchConfigurationConstants
at com.google.gdt.eclipse.designer.actions.deploy.DeployModuleAction.getGWTProjectClasspath(DeployModuleAction.java:364)
at 
com.google.gdt.eclipse.designer.actions.deploy.DeployModuleAction.createBuildScript(DeployModuleAction.java:150) 
at
com.google.gdt.eclipse.designer.actions.deploy.DeployModuleAction.access$1(DeployModuleAction.java:131)
at
com.google.gdt.eclipse.designer.actions.deploy.DeployModuleAction$1.run(DeployModuleAction.java:103)
at
org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)

Full stack trace (to see full context):
java.lang.reflect.InvocationTargetException
    at com.google.gdt.eclipse.designer.actions.deploy.DeployModuleAction$1.run(DeployModuleAction.java:114)
    at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)
Caused by: java.lang.NoClassDefFoundError: org/eclipse/jdt/launching/IJavaLaunchConfigurationConstants
    at com.google.gdt.eclipse.designer.actions.deploy.DeployModuleAction.getGWTProjectClasspath(DeployModuleAction.java:364)
    at com.google.gdt.eclipse.designer.actions.deploy.DeployModuleAction.createBuildScript(DeployModuleAction.java:150)
    at com.google.gdt.eclipse.designer.actions.deploy.DeployModuleAction.access$1(DeployModuleAction.java:131)
    at com.google.gdt.eclipse.designer.actions.deploy.DeployModuleAction$1.run(DeployModuleAction.java:103)
    ... 1 more