WP sIFR plug-in not working in FF3 on MAC

I’ve used this plug-in three other times in the past, all in FF3, and never had a problem. Now all of a sudden this plug-in won’t work for me in FF3. I read that AdBlock could be an issue. I’ve never had that add-on. All the other sites I implemented recently (with 2.9.2 WP) STILL work and I can login and see the plugin working great—and can see the sIFR on the site. With this new site—it won’t work in FF3 (I’m on a MAC) but I can see it in Safari. I even went as far as to disable and ultimately uninstall all the add-ons I had for FF, hoping that would fix the problem. It didn’t. Does anyone know a solution to this?

http://wordpress.org/extend/plugins/wp-sifr/