Instructions from Norton's Nathan:

    Norton Internet Security 2011 and Norton 360 version 5.0 are now compatible with the newest version of Firefox and Internet Explorer. If you have Norton Internet Security 2011 or Norton 360 5.0, run LiveUpdate until no more updates are available to get the compatability update for the Norton Toolbar. Once you have all available updates, restart your computer.

I am not sure what your going to do because Norton's instructions for any browser is to run update over and over.

Your question might be answered better Norton's forum http://community.norton.com/norton/?category.id=nis

I went to Help and Troubleshooting information and looked at Extensions and looked at Norton Toolbar and it was listed as True, Enabled for Version 6.0. I then installed 6.0 and have not had a single problem. This is just a good way to verify the download before doing it. Sometimes the download will list extensions and add ons that will not work after installation and other times it will not. I already had to wipe out Firefox last week because it automatically started the download and install. When I stopped the download, it destroyed Firefox so I could no longer use it. The error said there was "no point of entry." I put 5.0 back and now I have 6.0. Mozilla is making people work much too hard just for a rapid update every few weeks. They need to work out the bugs before dumping it on the public, instead of making us work out the problems for them.