I'm running Linux (Ubuntu Hardy) and used Gnash (the open source flash plugin). Then I tried to install Adobe Flash Player but it didn't help. Not until I uninstalled Gnash and reinstalled Adobe Flash Player I got to view the Family Tree properly.
I still have a problem with loading a family tree. I get the green tree with an arroe going around it but thenit finally gives and suggests that I refresh the browser and try again -- this does not work.