This is a PC issue, that seem to have arisen with the new patch.
Hopefully Scarberian's solution from another thread will help your situation.
I had this problem last week and what I had to do was goto evenbalance.com and download the program called "pbsvc.exe" and run it to uninstall PB entirely... Then use your "pbsvc.exe" to reinstall Punkbuster and check for updates(but it should install the latest version)... Also the PBSVC.exe comes with a test to check if PB is running without error...
If you are good with computers goto your SERVICES page in your Control Panel and check the pnkbstrA.exe and pnkbstrB.exe are both enabled and Started (after the uninstall and reinstall)...
Hope this helps it did for me...
Scarberian=HAR=