Punkbuster

Hello I got banned from a server and I got this message:

Game disconnected: you were kicked by PunkBuster. Stated reason: PunkBuster kicked player 'dpaunov21' (for 5 minutes) ... MD5Tool Mismatch: Update\Patch\Data\cas_50.cas (len=2048).

Then I read a forum post about it it says about removing the blue tint with fxaa injectors or something like that, I saw a link to a friend's FXAA injector a few days ago and even tho I dont remember it I may have installed it by mistake, I don't wanna get banned for such a stupid thing since ive got more than 800 hours played, and Ive loved every minute of it.

Can you please tell me how to fix  this problem? I don't really care about removing the blue tint, I like the game as it is.