I invoked a method on one of my EJBs and got the exception below on the client side. The problem is, this exception is quite misleading. I found out, that the problem went away after I corrected my EJB's method – It had a parameter which was not Serializable.
I suggest throwing a more meaningful AParameterDidNotImplementSerializableException in this situation – that would have saved me hours of debugging.

java.lang.IllegalStateException: EJBCLIENT000051: Cannot proceed with invocation since the locator StatefulEJBLocator{appName='wefend-server', moduleName='wefend-ejb', distinctName='', beanName='InstallBean', view='interface com.wefend.services.install.InstallService', sessionId='

'} has an affinity on node zirconium which has been excluded from current invocation context org.jboss.ejb.client.EJBClientInvocationContext@33c102c9
at org.jboss.ejb.client.ReceiverInterceptor.handleInvocation(ReceiverInterceptor.java:66)
at org.jboss.ejb.client.EJBClientInvocationContext.sendRequest(EJBClientInvocationContext.java:183)
at org.jboss.ejb.client.EJBClientInvocationContext.retryRequest(EJBClientInvocationContext.java:208)
at org.jboss.ejb.client.EJBInvocationHandler.sendRequestWithPossibleRetries(EJBInvocationHandler.java:256)
at org.jboss.ejb.client.EJBInvocationHandler.sendRequestWithPossibleRetries(EJBInvocationHandler.java:265)
at org.jboss.ejb.client.EJBInvocationHandler.doInvoke(EJBInvocationHandler.java:198)
at org.jboss.ejb.client.EJBInvocationHandler.doInvoke(EJBInvocationHandler.java:181)
at org.jboss.ejb.client.EJBInvocationHandler.invoke(EJBInvocationHandler.java:144)
at com.sun.proxy.$Proxy4.install(Unknown Source)
at com.wefend.observatory.install.task.InstallTask.call(InstallTask.java:91)
at javafx.concurrent.Task$TaskCallable.call(Task.java:1426)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:744)