[JXTA discuss] Weird symptom, jxta STOPS, any clues?

I had a reasonably well-working JXTA-based prototype, and I changed a  
few things in the application logic, miles (I thought) from the JXTA  
machinery, and everything has suddenly stopped working... I have a  
DiscoveryListener and it seems to be getting registered properly, but  
zero discovery events are occurring.

Before I invest a few more hours in diving deep on this (all this  
code was debugged months ago), any helpful hints at common things  
that people stupidly do that kill JXTA would be welcome.  -Tim