Abug in Flash CS3?

Question

I'm having this problem using Flash CS3. I put a movieclip
called "my_mc" in frame 20 and put this code in the first frame of
my movie:
gotoAndStop(20);
my_mc.gotoAndStop(2);
This should put the header into frame 20 and show the second
frame of "my_mc", but it doesn't work and the output shows this
error:
TypeError: Error #1009: Can't access a property or method of a
reference to a null object.
at Untitled_fla::MainTimeline/Untitled_fla::frame1()
This works perfect in Flash 8 but not in CS3. I don't know if
it's a program bug or there is another way to make it work. Anyone
knows?

Answer 1

The thing is that I don't want to put code in every frame I
want a movieclip to do an action.
I need to manage all movieclips from a class outside flash in
order to have all more organized.
I can't beleave Adobe couldn't fix this problem yet, if the
idea of Flash 9 is to have everything more organized in classes,
and not putting code in different frames and timelines of the
movie.
Flash 9 should have something like a map of all timelines and
movieclips in those timelines, but it doesn't seem to have it.
For example if I have an mc called "myMc" in frame 10 and
want it to gotoAndStop(3) and want the mc in frame 3 of "myMc" to
gotoAndStop(5) and a movieclip inside it but not in frame 1 to
gotoAndStop(8), I can't put code inside every movieclip because it
would be a mess. The ideal would be to manage everything from a
single class outside flash and don't put code everywhere.