I think you're right, but they don't seem to realize it. Scroll down to the bottom of this page I found:

http://www.fboweb.com/fb40/pu/info/gep.aspx#bugs

If I save it and rename it x.kml it does work. My installation is new (installed, removed and re-installed) and I of course have SP2.

Direct link to some interesting google earth flight tracking ... (see incoming flights at several busy airports in google earth)
http://www.fboweb.com/antest/ge/intro.aspx?old=1#

Thanks,
David