jbpm-console Error，java.io.NotSerializableException:javax.activation.DataHandler

[bulejava]

i just run example: Evaluation.bpmn

{ActorId=javax.activation.DataHandler@443d7f, Comment=Please perform a self-evalutation., Skippable=false, Content={reason=javax.activation.DataHandler@89cd90},2013/9/19 TaskName=Performance Evaluation}

ActorId  is also  a  javax.activation.DataHandler, but it has bean writeObject success

when writeObject content ,throws Exception.