I just tested the page on the same environment and everything worked like it did in the other browsers as well. Can you send a screen shot of the page not showing up correctly so I can compare? Also, does the admin pages of the PowerGallery work in other browsers or does it not work on any browser? When mousing over, there should be a button with a red x on it in the top right corner of the thumbnail and a button to rotate in the bottom right corner of the thumbnail.