Windows Messenger Wireless Problem

I have a wireless MR314 netgear router and I am trying to use voice conversation via my laptop with Win98se on it to my friend, on a dailup connection he can here me speak but I cannot here him but on a NTL broadband connection he cannot here me also I still cannot here him, but if I use netmetting we can speak to each other OK.Can any one help as support from NETGEAR is no good.