Can't select any image...

Dear all,

At one of my customer's website I can't select any images when editing or adding products or category in the admin. Never had this problem before. The OC version used is 2.1.0.1.
When I select any thing like: Parent, Refresh, Upload, New Folder, Delete, (the folder) banners, (the folder) inverted or just any image, the pop-up screen disappears and I see the next picture in the main window.
Selecting something from this page results in showing the image. I can not select any thing.
Permissions for all items are set on 777.

Who knows what's wrong?

It looks like page didn't load completely. Usually, this happens, when error occurs in the process. Try to look in the page source, at the end of it. There might be an error message.