we made the software work by
(a) turning off the windows firewall on the private network
(b) setting the mediaconnect application to run in windows 7 compatibility mode, as administrator.
With both PC projector and mediaconnect receiver (in DVD unit) connected to the wifi/wired router wirelessly, things performed poorly. When connecting the DVD unit to the router using a wired port things went rather better.
I think the problem is that the dvd wifi is 802.11b, thus downgrading the whole shebang – kinda like a UK MI6 spying-rock self-healing networking (of 1 rock). One cannot connect the wifi PDA to it too… to collect the spying records.