CFS3 Multiplayer problem.....advice please

[Reap]

I have CFS3 up and running on my pc, everything works fine until I try and do anything  with multiplayer.

As soon as I click the multiplayer tab on the left, the game locks up. If I try Ctrl Alt Del nothing happens and the only way I can do anything is to pull the plug.

Also if I try and go through the options tab to setup for multiplayer I can change player name for LAN etc but if i try and go any further, exactly the same problem.

I really want to play this on MP...can anyone help?

Thanks