mysterious error

I leave a router running with two machines connected: one is someone  
who comes and goes, and the other is a "continuity server" that stays  
attached to the router.

Sometimes I get an error like this one in the morning on the  
continuity server.  Can anyone tell me what I'm looking at? I don't  
know what the other person was doing when the error occurred. (They  
might have been going away -- e.g., having their avatar self-destruct  
after timeout.)