I'm not very familiar with the ins and outs of NDA's (Eileen?) but to me, material information is clearly spelled out:

http://www.investorwords.com/3011/material_information.html

http://www-us.practicallaw.com/8-578-5162#

There was an earlier post by someone which spelled out exactly what constitutes a material piece of information.

I can't imagine NDA's supercede the rules of the game.