1. Disable all screen overlay features in any running programs.If you want the long-winded WHY of this little bug, keep on reading.
2. If all screen overlay features are disabled and the problem persists, exit each program with a screen overlay and try again.
3. If FRAPS is installed, exit FRAPS and try again.
This was annoying to track down, as all things Punkbuster are, simply because Even Balance (the developers behind PB) refuse to SHARE with the community what their error codes mean or what may be causing them to kick non-cheating players.
Getting kicked by Punkbuster for "Disallowed Program/Driver 125120" simply means that a program or driver on the computer is trying to overlay something on the game-screen in a way PB does not like. This is a common way for hacks to hook into a game. Instead of interacting with the game, they sit on top of it with an overlay. This has been a common form of hack for years.
Unfortunately, Punkbuster recently made aggressive changes to how they view overlays and thus many programs that legitimately use them are now being seen as potential hacks by Punkbuster. Programs such as FRAPS and EVGA Precision.
Now, FRAPS in particular is having special difficulties. Older versions are flat-out interpreted as hacks by Punkbuster now and running any old FRAPS versions will get a player kicked repeatedly for "Disallowed Program/Driver 125120". Disabling the FRAPS overlay will not work. FRAPS must be shut down anytime a Punkbuster game is running. The FRAPS developer attempted to fix this problem in the current FRAPS version, but as quickly as they did, Even Balance changed Punkbuster to continue the kicking. So, its a tug-o-war between FRAPS and Punkbuster and I don't see FRAPS winning.
Other programs, such as EVGA Precision are in much better shape. Simply disabling the screen overlay features (such as GPU temperature) will fix the issue. This is most likely true for any number of overlay features in many video card manufacturer's software management/monitoring programs.
Unfortunately, for dedicated players of games like Call of Duty 4 or America's Army 3, this means the loss of some great software tools. Fuck Punkbuster. Once upon a time they were decent, but they've become the porta-potty of the anti-cheat world. No one wants to use them, they stink like shit, but unfortunately its the only option.