Box to insert link stays empty

Hi!

I am trying to insert a link in my post. I am in the visual ‘mode’ and select one word, after that I use the link button to insert a link. The screen that pops up just stays empty, really frustrating.

I could insert the links manually in HTML mode, but requires a lot of work, hopefully somebody has a solution.

I disabled all my plugins and the result was the same. Also I used different browsers; IE, FF and Opera.

Thanks!