have you restarted your OS? and do you have more than one firefox in your system? looks like you got a little bit messed up. my suggestion is remove all the firefox programs, including addons, and do a restart of your windows, and then download a new firefox 3.6.16/3.6.15 from mozilla official, do the install, then install the addons.

Thanks. I was able to get it to work. When I had 3.6 installed before, I was able to move the "refesh", "stop" and "home" buttons to the left side of the address bar. Now they are on the right and I can't find how to move them. Does anyone know how to do that? I really like them all on the left side.

it is easy, in firefox 4.0, just right click the buttons you like, then in the small menu, choose customize..., then a window of many buttons jump out, and DRAG (using your mouse) what ever you want there, if you are not that familiar with this, you can try Opera somewhat.

Thanks cityminz, but I'm not using FF4. I reinstalled FF3.6.