speculating a bit i would think that in-between client and server there is xml so either model should be valid as long as you have separate jars.
I've seen exact same error when generating Java with wsdlc using JAXRPC and deploy to weblogic with later versions of Eclipse (Juno).
Apparently Juno-Eclipse and previous can only run JAXWS models, even if deployment goes fine.
Workshop on the other hand uses JAXRPC model.
Using a build file and deploy outside Eclipse should work.