The same problems occurs with me, but i am using Gaia Framework... I replaced the folder "com/greensock" by the folder of the pack Club Greensock in the project and recompiled all the project but i receive the same error message:
"Error: LiquidStage warning: please update your TweenLite class to at least version 11.51 at http://www.TweenLite.com.
But my version is 11.68, and i have tested in a normal project without Gaia Framework and it works!!
Probaly it's a Gaia bug..