[Plugin: Geolocation] IE doesn't display map. Opacity issues?

Hi,
great plugin, well working in Firefox.
Instead, in IE I cannot see the map, but only Google logo, the map pin and magnification-reduction commands, such as the map was “transparent”.

See one of my maps.
What is the matter?

Thanks in advance for helping
Ines

http://wordpress.org/extend/plugins/geolocation/