BF2S Forums Pb Guid?

Hi, I've just signed up in the 2v2 chopper-ladder in TWL, and there I need my PB-GUID. It says there that I can find it by typing in /pb_plist in my console ingame in a server with Punkbuster. But I have tried it in many servers, and I get the message "Error: Wrong Syntax!". I've also tried without the "/". Does anyone know how to get this GUID?

Very grateful for any answers!