Voice issue for Jonathan Kay

I been trying for a long time to find out why the voice
don't work on Msn 6.1 & windows messenger for a long
time, I think the problem is in the IP/tcp Protocals that
we use in the networking area. When we installed the XP
update for Advanced Networking Pack for Wndows XP we lost
the voice unless we took of the windows firewall,we never
had this problem before,we never had to shut it off. If
we revert back to the old generic IP protocal we get the
voice back.Now here is the hitch. when we go to uninstall
the XP Advanced Networking pack it gives you a whole list
of programs that it says it could affect I put the
generic IPV6 back & all seems ok, but I can't figure what
in the new version 6 is causing it. I would like to use
Version6.Maybe you can look into it on your end having
more practice with registry, please let me know your
thoughts.

Thanks for your time,
Carmine