Diagnosis for unreproducible error.
java.lang.IllegalArgumentException: argument type mismatch
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at hudson.remoting.RemoteInvocationHandler$RPCRequest.perform(RemoteInvocationHandler.java:299)
	at hudson.remoting.RemoteInvocationHandler$RPCRequest.call(RemoteInvocationHandler.java:280)
	at hudson.remoting.RemoteInvocationHandler$RPCRequest.call(RemoteInvocationHandler.java:239)
	at hudson.remoting.UserRequest.perform(UserRequest.java:118)
	at hudson.remoting.UserRequest.perform(UserRequest.java:48)
	at hudson.remoting.Request$2.run(Request.java:328)
	at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)