The new rapid release development cycle has bit Mozilla in the rear. For example, FF 7.0.1 on Vista needs to be run as Administrator. I didn't find this out until it just stopped working on my wife's laptop.
The automatic updates have to ask for admin rights, is that what you are seeing? You can deny admin rights and it will run fine (without updating). And they know it's not optimal, they're fixing that in the next version.
