NAV 12 for Mac Won't Install

I purchased NAV 12 for Mac directly off Symantec website. It CLEARLY said that it includes v.11, which supports my OS 10.6.8.

 

Downloaded my NAV but it won't install because it says "Norton AntiVirus Installer requires Mac OS X version 10.7 or higher."I don't have a disk because I downloaded it online.

 

Now what? Why claim that it includes v.11 for 10.6.8 if the installer requires 10.7?