Weird Screen saver preference pane's behaviour

[koyi]

Help!!!

I think I mess up with something of the Screen Saver preference pane. It used to display "Choose folder..." so that I can use a slideshow of my own pictures as screen saver. But now that option is gone entirely!!!

Another weird behaviour is that, the "Computer Name" screen saver used to display the name of the computer as the screen saver, but now its icon became a folder, and when I select it, it prompts me for a directory, no matter what directory I choose, the "Computer Name" screen saver doesnt work properly as it used to work.

What is all the things behind all this? Is there any plist that I should delete to get things back to normal?

Thanks.