Hi mate.
Never played with windows 8 although had a look at it recently and it looks to me like they have just slapped the tile system on there instead of the start menu, I can't imagine there is any difference with the .Net framework in any case.
make sure the cm0102.exe's properties are correct (NT4.0 compatibility and run as admin)
and make sure you have deleted the
cpuinf32.dll file from the data folder.
For LAN games you will need to check out the network card's ip address which will usually be 192.168.xxx.xxx and can be found in adapter settings
dynamically assigned ip addresses can be an issue here and it's wise to manually assign ip addresses to all computers (network cards) that wish to join the game.
Also if you are playing a pure LAN game, the computers need to be
physically linked up on the same network
Wireless may not work, unless you use hamachi (which simply makes the computers believe they are physically linked in the same room/network by ethernet)

You say the ip in the net file is correct but just do a quick check in game settings/manager status screen to see what the ip is, then anyone joining can type that ip instead of the game name.
However if the game can't be created you can't get this far, so just double check the net out file has the same ip as the network card.
The next thing to check, and in 90% of cases the thing that causes the problem, is the security settings of the hosting computer. I know you haven't actually got to the point where the game has been created but a potential pitfall is also your PC seeing the others joining as a threat and blocking access. In that case
"the network game 192.168.xxx.xxx could not be joined"
will be the error and disabling security and firewalls will usually sort this out.
Let us know how you get on and an idea is also to install hamachi and join the champmanclan group.
There are usually a few guys on there that will be happy to help