Newb question

I’m hoping someone here can help me out. I just used the tutorial for getting a popup window to appear center from this site. Works great, but now the only thing I can’t get working is having multiple buttons load images into that one window. You can see what I mean if you jump to my site and goto artwork/daoc darkness rising, then click on any of the seven images to the right and the window will load correctly, but if you continue to press other thumbnail images it will not update the window correctly. The only way it will is if you close the window then click on the thumbnail which I don’t care for so much since I rather let the user leave the window up as he or she browses my work.
If anyone can help me out I would greatly appreciate.

aka PolyMonkey

p.s. I’m aware that the imperator section does not have unique thumbnails and the other projects don’t launch the full size images. Site’s still underconstruction =).