Flash Array question

Ok, here goes the description.

I am building a dynamic slide show. The problem I am having is that when I create the slide movieClips, the movieClips that are generated inside of them are not generating.

If I declare an array and name all the slide names within the actual flash it works fine:

_global.mcName = new Array(slide0, slide1, slide2, slide3, slide4, slide5, slide6, slide7, slide8, slide9, slide10);

for (i=0; i <m; i++) {
mcName[i].createEmptyMovieClip("slideMask", 1);

}

If I try and generate the array inside a for loop with "mcName.push(name_array[i].firstChild)" it generates the slides but not the sub-movieClips. Such as:

_global.mcName = new Array();

for (i=0; i<m; i++){
 _global.mcName.push(nameMC_array[i].firstChild);
mcName[i].createEmptyMovieClip("slideMask", 1);
}

Any help here?