Can somebody please tell me why this is going wrong?
Ive had a look around and sometimes my code works but then sometimes it does this. Does this error have anything to do with the serialVersionUID and can somebody tell me what a serialVersionUID is?

javax.jms.MessageFormatException: IOException: com.btexact.erica.billing.EUBillingEvent; Local class not compatible: stream classdesc serialVersionUID=-58111460479134682 local class serialVersionUID=-5214677529919586059

The simple piece of code that can regenerate this error is:

if (message instanceof ObjectMessage)
{
System.out.println("Message is instance of object message");
ObjectMessage msg = (ObjectMessage)message;
objecttype = msg.getObject();
}

Any help???