that message means punkubester service cannot be reached.
Either you didn't install piunkbuster correctly, pknbstrA service is not started, pnkbstrB cannot be started or the two cannot communicate with each other.
1) make sure your PB install is correct- if you reinstalled ET you will have to install PB manually probably - go to evenbalance.com and follow their manual
2) make sure pnkbstrA is started
2a) go to Start menu -> Run
2b) type "services.msc", press enter
2c) look for service named pnkbstrA - is it there?
2d) if you found pnkbstrA service, what are values for Status and Stratup Type?
3) if you changed anything in the process while you dind't know what you were doing, you're screwed.