from your reply,you have put the correct address (
http://IPAddress:9000/DeviceDescription.xml)
" The WD TV Live HD player works happily with the Iomega HMND - so the Iomega media server is certainly working. "
The Iomega HMND can be accessible by the WD TV Live Media Player either as
a Samba Device or
UPNP/DLNA streamingAirplayer use UPNP/DLAN only, so please help check the UPNP/DLNA in Iomega HMND is working .