I don't get this..

Everytime I start Crossfire, it loads fine, but..
After the check of the HGW Game Watcher sh.it, it goes to a full screen black window (still a little bit normal, I'm used to that anyway). But at that black window, it shows an error after a few seconds..

This error is:

"Client file corruption detected, Closing game client."

How can I solve this?