Vista - Internet Explorer Add-on Installer

I just tried to access a National Weather Service site to view radar images
(because of local weather warnings).
http://radar.weather.gov/radar.php?r...t=NCR&loop=yes

When trying to view the Composite Reflectivity Loop (enhanced version), the
Information Bar popped up telling me that IE had stopped the site from
installing an Active-X control. When I clicked to install the control (I
certainly trust _this_ site), the User Account Control came up and asked
for administrator permission to install the control. I clicked continue
and then got back the message that "Windows has blocked the software
because it cannot verify the publisher." There was no way I could
continue.

How do I override this flakey protection that completely prevents me from
viewing the time-loop images?

Dr. Barry L. Ornitz