From MozillaZine Knowledge Base
A number of newer Logitech mice use SetPoint™ drivers. Some versions of the SetPoint™ drivers (ex: older versions on mouse CD) have a problem with the back and forward buttons not working with Firefox. To fix this, use the support download link below to download the updated Logitech drivers for your model. Alternately, you can follow these instructions to make it work.
Select product and product name at http://www.logitech.com/index.cfm/support_downloads/downloads/&cl=us,en to find latest SetPoint version for the mouse your using.
Mice that use SetPoint™