[jbpm-dev] jbpm5.4 exception

Hi ，every one The attachment is bmpn files.It is an ask for leave example.The currentUser parameter is current login user;employee1,employee2,employee3 is potential task owner,it is usually Leader-Member relationship(maybe employee1 is currentUser's manager,user myself organization structure from database to judge);the hasManager parameter represent whether some people has manager(boolean);the result parameter is every task owner's opinion(boolean,reject or agree) ,if reject,the work flow will get back to original user;the comment parameter is some suggestion.before task owner sign,user could view previous task comment and owner user.At present, this process will throw exception like below when employee1 agree or reject.Maybe the constrains of diverge gateway(id 12) is wrong.can you help me? thank you very much!!! the exception like that: Exception in thread "Thread-16" com.thoughtworks.xstream.io.StreamException: Cannot create XmlPullParser at com.thoughtworks.xstream.io.xml.AbstractXppDriver.createReader(AbstractXppDriver.java:56) at com.thoughtworks.xstream.XStream.fromXML(XStream.java:912) at com.thoughtworks.xstream.XStream.fromXML(XStream.java:903) at org.drools.process.core.datatype.impl.type.ObjectDataType.readValue(ObjectDataType.java:77) at org.jbpm.workflow.instance.node.WorkItemNodeInstance.triggerCompleted(WorkItemNodeInstance.java:223) at org.jbpm.workflow.instance.node.HumanTaskNodeInstance.triggerCompleted(HumanTaskNodeInstance.java:90) at org.jbpm.workflow.instance.node.WorkItemNodeInstance.workItemCompleted(WorkItemNodeInstance.java:309) at org.jbpm.workflow.instance.node.WorkItemNodeInstance.signalEvent(WorkItemNodeInstance.java:285) at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.signalEvent(WorkflowProcessInstanceImpl.java:342) at org.drools.process.instance.impl.DefaultWorkItemManager.completeWorkItem(DefaultWorkItemManager.java:116) at org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler.handleCompletedTask(GenericHTWorkItemHandler.java:271) at org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler$1.run(GenericHTWorkItemHandler.java:239) at java.lang.Thread.run(Thread.java:619)