I bought + downloaded bf 2142 from the EA Downloader.  I played since release on the 18th.  First day no punkbuster kicks.  2nd day it started, I play alot but.. 15-20 kicks per day.  Last night I noticed a message for the first time "PB Important: Duplicate GUID/CDKEY" and its happend about 7-8 times today already.  Can't go 30 min without it seems like. 
  
As soon as I notice it at the bottom of the screen, it waits about 5-10 seconds before it boots me and I look up at the top of the screen and see someone else being kicked by punkbuster at the same time.  Always happens like this.  But I read somewhere else that its your own cd key getting duplicated when you lag and reconnect to the server- your "ghost" causes it.  /shrug 
  
I did the fix suggested on evenbalance.com, didnt seem to work.  Sent customer support to EA/bf 2142 but they are swamped so it will probably be a while before I get any feedback.