help with LANning RA3!

[diablo6speed]

I have a little lan set up with me and my roomates. We can all go on line and play quake in the same server just fine. but whenever i try and create my own game and have them join it, it kicks them out. It shows them connecting to server and just about before it would let them in, there kicked out. The weird thing is that sometimes it lets them in. Thats a very rare chance though, it usually just kicks em. I get the same results whether i run the batch file server or just goto multiplayer and click create. Pure server is off as well. thanks for ur input!