Would you try it with a default joomla template? Your template is based on html5 - did you write it yourself?
You are also loading jquery on the page (joomla and hotspots they use mootools - it is not recomended to have 2 js libraries loaded on the same page).
To be honest right now I have no idea. For me the map on your site doesn't load at all - all what I get are several messed windows. (checking the demo page
demo.compojoom.com/hotspots
one more time with IE7 proves to me that hotspots works on IE7 - something on your site must be braking it).