I had the same problem; to fix it try this.
Turn off your VOIP in your audio controls. I belive that that is the main problem. Also, make sure that when you update your punkbuster that you place the HTML files in the "pb" folder found in your Battlefield 2142 program folder, because when punkbuster scans your system it looks in the "pb" folder for the updattes. It should be something like Program Files-->EA GAMES-->Battlefield 2142-->pb-->html.
I'm not sitting in front of my desktop so I don't know if thats exactly the path, but its close enough and will be easy to find. I would recomend saving the updated punkbuster files to the desktop and then transfering them to the pb folder when finished. Next just restart the computer.
That should take care of the problem. If this works for you let me konw and i'll make a faq's page