Flashspeak...

the root timeline is the timeline in the main movie...ie not a movieclip

you can add actionscript to it by selecting the score/timeline dialogue (clock on the toolbar) select the third tab down on the left....click on '+'...
choose 'actionscript'...and add the lines in the dialogue box.

The easiest way to access after that is through the 'movie overview'...right click...edit

the two lines mentioned are only needed for the first method.

hope this makes things clearer...

mike