testJavaException and testSpeedJavaException of ExceptionTimingStressTestCase fail consistently on IBMJDk

https://jenkins.mw.lab.eng.bos.redhat.com/hudson/view/EAP5/view/JDK7/job/eap-5.2.x-IBMJDk7-RHEL5-matrix/lastCompletedBuild/jdk=ibm17,label=RHEL5_x86/testReport/org.jboss.test.excepiiop.test/ExceptionTimingStressTestCase/testSpeedJavaException

Stacktrace

java.rmi.MarshalException: CORBA MARSHAL 0x0 No; nested exception is:
org.omg.CORBA.MARSHAL: unknown value tag: 0x4 (offset=0x2124) vmcid: 0x0 minor code: 0 completed: No
at com.ibm.CORBA.iiop.UtilDelegateImpl.mapSystemException(UtilDelegateImpl.java:279)
at javax.rmi.CORBA.Util.mapSystemException(Util.java:84)
at org.jboss.proxy.ejb.DynamicIIOPStub.invoke(DynamicIIOPStub.java:149)
at org.jboss.test.excepiiop.interfaces._ExceptionThrower_Stub.throwException(Unknown Source)
at org.jboss.test.excepiiop.test.ExceptionTimingStressTestCase.testSpeedJavaException(ExceptionTimingStressTestCase.java:146)
at junit.extensions.TestDecorator.basicRun(TestDecorator.java:24)
at junit.extensions.TestSetup$1.protect(TestSetup.java:21)
at junit.extensions.TestSetup.run(TestSetup.java:25)
Caused by: org.omg.CORBA.MARSHAL: unknown value tag: 0x4 (offset=0x2124) vmcid: 0x0 minor code: 0 completed: No
at org.jacorb.orb.CDRInputStream.read_value(Unknown Source)
at com.ibm.rmi.io.IIOPInputStream.readValueType(IIOPInputStream.java:2561)
at com.ibm.rmi.io.IIOPInputStream.readObjectField(IIOPInputStream.java:2539)