Can't acess facebook where INVALID URL were shown

Can't acess facebook where INVALID URL were shown

I can't access the facebook webpage only for every browsers of my mac os X (firefox and safari), while others website are not affected. I've try so many ways to fix it, including OpenDNS, terminal, clearing caches and I even restore the caches from the trash in my laptop & etc., but still seems like doesn't work. The message is shown as below:

Invalid URL The requested URL "/", is invalid.

Reference #9.3e556acb.1338053744.2cbad993

What should I do and what cause it happens?

In addition, I feel like it happened after I clear my caches through the MacKeeper.

Thanks for helping!