Problem with Admin Options

Hi. I have a problem with my forums. All works perfectly except for the admin options. Everytime i go there to change things and when i try to save a page cannot be displayed appears. All the other link in my admin panel works. But the admin options open, just that when I hit save it takes too much time to save and it doesnt save it, it justs says page cannot be displayed.

I need help cause I want to change the forum title and stuff.
Please respond me as soon as possible and tell me how to solve the problem.