I recently need to run multiple clients to test something but was informed you can only run 2 Clients. I did some googling and there are other ways but I came across this and it simply just works.
Start LottaCam. From then on, until you reboot, you can launch as many copies of DAOC as you want.
You can use any program that can delete the MuteX of the game.dll. i use a program callrd Process Explorer, or i use Mojo. Used to also have a macro with HotKeyNet haha