Asterisk, X-Lite, no sound

I’m using X-Lite with an Asterisk@Home server, I’ve tried the phone on several different laptops and desktops, all running Windows XP. I’ve tried both on a LAN and over the Internet. I’ve searched these forums and have opened all the appropriate ports, even put the server in the DMZ. Audio tuning wizard shows everything as working, can get the phones to connect, will ring but once picked up, no sound. When I check voice mail all the messages are 0.04 seconds long, would appreciate any help, thanks.