Problem with setting source path in Flash Builder

Question

In trying to learn ActionScript in FlashBuilder, I ran across a Library that needs to be added to my project.  The code is at http://www.rightactionscript.com/ascb (the ascb.display package).  I have tried placing it in several directories on my hard drive and setting the build path to those directories (Projects -> Properties -> ActionScript Build Path), but get an error (non-verbose, i.e. no explanation) on attempting to run the code.  Within FlashBuilder, the classes show up in the Package Explorer, and the code completion works fine....what am I missing?

Answer 1

Yes, mc1 and mc2 are both on the root timeline. The similar issue is that using a relative path does not work. Its been awhile since I used Flash and could do wonders with AS 2, but AS 3 is hard to get used to. (second nature to start typing _root...). I was told to avoid absolute paths and vars, and use events. What is the best way to have a movie clip play and then tell another (sibling) movie clip to play when it reaches a certain frame? When mc1 stops on frame x, the code below runs. The commented line is the one that does not work.
var fl_SecondsToCountDown:Number = 1;
var fl_CountDownTimerInstance:Timer = new Timer(1000, fl_SecondsToCountDown);
fl_CountDownTimerInstance.addEventListener(TimerEvent.TIMER, fl_CountDownTimerHandler);
fl_CountDownTimerInstance.start();
function fl_CountDownTimerHandler(event:TimerEvent):void
Object(root).mc2.play();
//Object(this).mc2.play();
fl_SecondsToCountDown--;