Wall problems?

I can't comment on wall posts anymore nor can I post on people's walls. Clicking on "add a comment" only leads me back to the top of the page. Pressing enter to make a post just gives me a text saying "You cannot post an empty message." The post button is also missing. It worked perfectly this past week until today (I don't remember any settings being changed).

I've cleared my cache and restarted my computer but this didn't solved it. Any help and suggestions?
I'm using Internet Explorer 9.