Simple attachMovie question

Adobe Flash CS3
publishing as Flash 8, AS 2.0

i have a movieclip named menu (instance name = mainmenu).
inside of that there is a button named btn_about (instance name = about).
on the main stage there is an empty movieclip named empty_mc (instance name = mcholder, linkage id = empty)
i want a user to press the button which causes a movieclip in the library named tesst (Linkage name = testid) to load into the empty movieclip (mc_holder).
Here is the code on the button:

on (release) {
this._parent.mcholder.attachMovie(“testid”, “tesst1”, this.getNextHighestDepth());
}

it does not work and i’m pulling what’s left of my hair out. any ideas?

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