Crossfire dont open

Hi.
I cant join in the game Crossfire. If I try to start the game... following error comes:

Some functions of the operating system has been corrupted. Please, close any program which is affecting game client an restart system.

But i dont have any hacks or sth. I tried the Tutorials on the Crossfire forum too. I closed antivir program and reinstalled the game etc. I tried all! But it dont works.
Please help (: