Microphone not working in Netmeeting

WE can both send video and the other party can hear us, but we cannot hear them. They have gone through “sound recorder” (they are running 98, we are running xp), and the microphone is testing fine on their computer but it is not workign once in netmeeting? Any ideas? She at one point said that she was hearing her voice reverbing back to her on netmeeting. I have tried all i know to try. Please help. Thanks!