For those of you who have patched Underworld to 2.24 and use the 2.21 NO-CD (Which works by the way) you may have noticed you can't host multiplayer games. You can connect to anyone running a 2.21 multiplayer game though and if you use a 2.21 version of gameserver.exe, you can host multiplayer games and connect to them as well.
http://www.upload2.net/page/download...erver.exe.html
Here is a link to a 2.21 version of gameserver.exe for Sacred Underworld.