I also have difficulties with Hotspots on one of my websites. There is currently only a single category and a single marker, but the map never displays and a "Loading Data" window is displayed continuously. The direct link for the map is:
http://www.quebecoiseaux.org.
Strangely, the application works fine on another website hosted on the same server. The application has been installed in the same way. See :
http://www.coim.quebecoiseaux.org.
Thanks!