Hi - really sorry to drag this ancient issue up but I am experiencing the exact same problem. Thing is I am using a fresh download of the AS3 greensock library (downloaded today) in a completely new Fla which does not subload any other swfs.
The problem does not go away whether I use import com.greensock.*; or import com.greensock.TweenLite; but it does let me import the library because the errors are only thrown when I try to instantiate the library.
EDIT:
Ok this is solved and I am an idiot - I had a movieclip named 'Animation' in my library which was causing a conflict with the core Greensock class Animation. Please delete this thread and my account because I do not deserve to use your library!
