Norton toolbar doesn't work in Firefox

I've got a strange problem with the Norton Toolbar in Firefox.

basically, the toolbar appears but I can't do anything with it. When I click on the three little dots for example (which should display the toolbar settings menu) nothing happens.

I've tried completely uninstalling both Firefox and Norton Internet Security and re-installing them but the result is the same.

Using Windows 7 by the way. Anyone seen this / know how to fix it?