need help with strange java error

when we tested this morning on one server, we still received the error, so i don't think it's persistence related as they got the same error on a single server

 

 

the only thing that confuses me (based on what you said about cookie sessions not expiring) is that when they receive the xml error it kicks them out of the site, and they have to log back in. however, at this point we can see that they're been load balanced on to another member. how is this the case if they're using standard cookie persistence and there's been no time delay and they've not closed their browser?!

 

 

thanks again