Instance name of MovieClip that was created with addChild() func

Hi All.
I had made a MovieClip obj and put it on the stage with addChild() function in my .as class from one of my library MovieClip object of my .fla project…

I have one another MovieClip inside of that MovieClip, and now, I want do something on that with as3 code…
code is something like that:

// in .as class
addChild(mc1);
mc1.name=“mc1Name”;

// in root of .fla project
MovieClip(root).mc1Name.mc2.dyntext.text=“some text here!”;

mc2 is inside MoveClip and dyntext is Dynamic text control on that…
But when I run my project, I have this Error:

Error #1069: Property not found… :jail:

Do u have an idea?!!