Norton Toolbar won't install on Firefox

I am trying to get the Norton toolbar to install on FF 3.0.5 running on a Sandisk U3 thumbdrive.  The toolbar is installed and works fine on IE and FF running on my PC.  I use the Sandusk U3 drive on the dsame PC, and would like the toolbar installed on FF installed on the thumbdrive.  I am running Norton Internet Security Version 16.2.0.7 on my PC.