Can't add images to pages

If there is anybody out ther who has a solution for this, that would be seriously appreciated! I am trying to add images to pages, and the “add image” button does absolutely nothing for me. I mean nothing. We also use this slideshow plugin http://wordpress.org/plugins/slideshow-jquery-image-gallery/, the add slide show button for which equally so does not function. The other thing I noticed is that when the “add images” button does not function, the “Screen options” and “Help” drop down lists don’t function either. The various drop down lists i.e. “Author” don’t function either, but the fly-outs from the side menu do work. However…

If I am on the dashboard home page, and use the “add images” button in the quickpress section, it functions without any hassle. I can also add featured images to pages, without any problems.

I have cleared the cache, disabled all the plugins (indeed, ALL of them :)), no joy. I’ve tried to add images using both firefox and Chrome, no joy. I’ve added “define(‘CONCATENATE_SCRIPTS’, false );” to wp-admin.php as suggested in another post somewhere, no joy.
I really do not know where to go with this. At the moment we create the html code for the image in question in Quickpress and then copy that code into the html editor on the page we need the image on, which works. But it’s not really the way it should be done…