It's hard to say whether this is explicitly causing the problem but the interfaces should not be defined to implement Serializable. Remote ejb reference objects are special container objects that can automatically be passed as parameters and return values. Marking an interface Serializable is not part of the ejb programming model. The only objects that are directly serializable from the application's perspective are the legacy EJB 2.x Remote handle objects, which don't apply here.
Also, these are all remote interfaces right? Local ejb references can not be passed outside of the application in which they are defined. Was this example executed with the interfaces still packaged in the app server lib directory? If so, please remove them and after making the other changes rerun the example. If things are still not working please file an issue.
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