You're welcome.

I've saw this occurrence once before, due to FTP's naughty file droppage and so forth. So, I checked your page source and found;

<script type="text/javascript" src="includes/templates/template_default/jscript/jscript_imagehover.js"></script>

That doesn't tell me much, but it does tell me that at least some of the files are in place... but, the style_imagehover.css seems to be missing from your current template. Check the original zip file of the Image Handler and just do a desktop/online file comparison, a basic seek and replace mission.

You should really consider upgrading or do a fresh install with v1.3.5(along with the latest patch). That template you are using is obsolete now and it bring you woe down the line. Now would be the perfect time, seeing how your store is somewhat new.