Popup windows doesn't show in the visual editor. Just som text below the page..

WordPress 3.5.1 and Nextgen 1.9.12 versions and the standard visual editor on a Linux server. The client is a Macbook Pro with OSX 10.8.3 (the latest version of the OS) and i have tried Chrome, Firefox and Safari browsers. Popup windows are not blocked in the browsers so the problem lies elsewhere.

Problem: When I use the visual editor to create a post or a page and click on the Nextgen icon the popup never shows and instead there is an ugly addition to the bottom of the page that I have to scroll down to for adding photos and slideshows to the post or page?

I have also tried another computer form and get the same result and that makes me assume that it is some server or WP or NextGen settings but I am not able to find it……