OMG ill know that kind of problems! Beqause I spend lots off time on this pretty anoying problem and fixed it in lots of time > ill try to help you forward...

Ill think you need to check the following things:

- Change your dynamic Ip adres to a Static one see the link below here.
http://www.portforward.com/networking/staticip.htm

- Forward the ports in your router that jazz2 need (see on the site)
(ill set port 500 t/m 50000 open in my router for getting rid off the *** security.

- Something about security: Your modem/router maybe have some off this anoying content. I did disable my firewall and stuff.
With Windows firewall u can make an exception for jazz2 that it don't block it annymore.

Succes!