a Hibernate mapping POJO may be serialized to remote web app?

[Robert Strong]

I'm using hibernate in Weblogic8.1 Stateless session beans. I have a Hibernate mapping POJO which implemented java.io.serializable interface, at first, this POJO was able to be serialized to remote Web App after initialization. But when this POJO is associated with another Hibernate mapped POJO, I'd receive following exceptions:

java.rmi.UnmarshalException: cannot unmarshaling return; nested exception is:
java.io.InvalidClassException: com.emart.hibernate.Category; local class incompatible: stream classdesc serialVersionUID = -6982780474976627114, local class serialVersionUID = 8550007601317391344

could anyone here help me out?