!! Host Error !!

Some times (means a lot), when i try to enter a room, some times i just try to drop out, a screen comes and take me as prisoner. Even if i click OK (the only thing i can do), that window pop-up, and keep appearing every OK i click. And it's cyclical. I only have the old CTRL + ALT + DEL ! If this issue deserves attention, plz make it stop. Thanks a lot. BTW since i get back playing some FPS, CF is far the better one!