ChangeWatcher

Hi all, I need help to do this:

“Make sure you add the flex framework.swc to your project Library Path to have access to the mx.binding.util class.”

The above is what I need to do to get the ChangeWatcher to work in AS3 CS4 accrding to:
http://www.dreaminginflash.com/2008/07/29/flex-bindings-in-as3-projects/

So How do I add that framework.swc to my project Library Path?
Pls spell it out for me - like where do I download that .swc thing?
Note I only use Flash in CS4 and have no clue yet as to what FLEX is…

Pls advice,
Jaxz