OK, a while back I got some friends together, and tried to have a Doom 3 LAN party. I started a server on one of the standard maps, but when other people tried to join, it kept telling them “Missing 4 media PAK files.” If someone else hosted, this wasn’t a problem. Aster some troubleshooting, I took the 4 custom MP map PK4’s I had out of the base directory. After that, people could join just fine. It looks like, at least on a pure server, you must have all the same PK4’s as the server to join, even if some of those PK4’s aren’t used. So For servers with custom maps, you either can only have the maps you want to play on the server, or not run a pure server.
Anyone else have this problem?