I can't tell where the IllegalStateException originates from as the Gump log doesn't show the stack trace of that exception. However, I came across some non-threadsafe code in AddressBookSOAPBindingStub:
if (firstCall) { firstCall = false; (generated by org.apache.axis.wsdl.toJava.JavaStubWriter), so I wonder if that might be the cause? Getting the stack trace would be a help in this situation, even if it only points to an object which has been corrupted earlier, so I've added fatal error logging to the testcase to ensure Gump records the details. Glyn