Duplication problem

I have a movie clip that I am trying to duplicate with the following code in the first key frame

myVars = new LoadVars();
myVars.load("array.txt");
myVars.onLoad = function() {
	varArray = myVars.arrayValue.split(",");
	varLength = varArray.length;
	i = 0;
	x = 0;
	for (i=0; i<varLength; i++) {
		createEmptyMovieClip("movie_"+i, i);
		_root.masterm["movie_"+i].loadMovie("thumbs/"+varArray*, _root);
		_root.masterm["movie_"+i]._x = x;
		_root.masterm["movie_"+i]._y = 0;
		x = x + 68;
	}
};

this works great when I have the clip placed already on the stage. My problem is that when I duplicate the clip this:

masterm["movie_"+i]

just updates the parent movie. How would I be able to change the “masterm” to the name of the duplicated movie?