NoClassDefFoundError: GuiceServletContextListener when running GWT + GAE from Eclipse

When trying to run my project as a WebApplication from Eclipse, I have the following error:

[WARN] failed com.google.apphosting.utils.jetty.DevAppEngineWebAppContext@4b903fd{/,D:\Dev\Projects\The Five Orbs\trunk\target\fiveorbs-0.1}: java.lang.NoClassDefFoundError: com/google/inject/servlet/GuiceServletContextListener
[WARN] failed JettyContainerService$ApiProxyHandler@eb4d977: java.lang.NoClassDefFoundError: com/google/inject/servlet/GuiceServletContextListener
[WARN] Error starting handlers
java.lang.NoClassDefFoundError: com/google/inject/servlet/GuiceServletContextListener

The class can be found at compile time though (my custom GuiceServletConfig extends GuiceServletContextListener and compiles properly).

The guice-servlet-3.0.jar library appears both in the project build path and in the classpath of my Web Application Run Configuration in Eclipse.

The Arguments panel of my Run Configuration has the following config: in Program arguments:

-remoteUI "${gwt_remote_ui_server_port}:${unique_id}" -startupUrl TheFiveOrbs.jsp -logLevel INFO -server com.google.appengine.tools.development.gwt.AppEngineLauncher -port 8888 -codeServerPort 9997 -war "D:\Dev\Projects\The Five Orbs\trunk\target\fiveorbs-0.1" com.fiveorbs.TheFiveOrbs

in VM arguments:

-javaagent:D:\Dev\Programs\appengine-java-sdk\lib\agent\appengine-agent.jar -Xmx512m -Dappengine.sdk.root=D:\Dev\Programs\appengin开发者_如何转开发e-java-sdk

When I run mvn gae:run from the command prompt with Maven, everything is fine though - the server starts properly and no exception is shown.

I have been struggling with this issue for a couple of hours, and really cannot fathom why it occurs.

Thanks in advance for any hint you might be able to offer.

Sébastien

guice-servlet-3.0.jar should not be in you launch configuration classpath, it should live in your D:\Dev\Projects\The Five Orbs\trunk\target\fiveorbs-0.1\WEB-INF\lib folder.