Why does Punkbuster kick me when I join BF3 servers?

I enjoyed Battlefield 3 on Xbox, so I signed up for EA Origins and bought the PC version. However, every time I try to join an online match, Punkbuster kicks me from the game before the window even opens:

The message says "RESTRICTION: Service Communication Failure: PnkBstrA.exe". What does it mean? I've tried re-installing PunkBuster, Origin, and Battlefield 3. I'm running Windows 7 with only Steam, Silverlight, and mouse and game controller drivers. This is infuriating.