Popups not working

When first tinkering with Nagios and before I had customized the icons on the status map, the popups worked. Now that I’m using my own icons, the popup window does not appear anymore for any of the hosts in the map.

The icons themselves seem okay as they appear to be fine in the map and in the host details. I’ve tried visualizing the map with Firefox 2 and 3 and IE 7

Using Nagios 3.0.2.

Any help would be greatly appreciated.
Guy