Digium: The company who made and maintains Asterisk...
G.729 licenses: You must pay the inventors of G.729 money to use this codec (a method to encode and decode sound). While Digium did not actually invent G.729 they have the rights to resell G.729 licenses...
Unless you really have bandwith constraints or another similar reason I would get rid of G.729 and use G.711 instead...
For G.711 since its patent expired a long time ago you don't have to pay anything...
Have a nice day!
Nick