Problem with dynamic mask

I am dynamically loading an image which I am dynamically trying to mask. Can anyone tell me what I am doing wrong?

[AS]
_root.createEmptyMovieClip(“clip1_mc”, 1);
_root.clip1_mc.createEmptyMovieClip(“photo_mc”, 1);
_root.clip1_mc._x = x;
_root.clip1_mc._y = y;
_root.clip1_mc.photo_mc.loadMovie(“pics/pic1.jpg”);
_root.clip1_mc.photo_mc._xscale = 100;
_root.clip1_mc.photo_mc._yscale = 100;
_root.clip1_mc.attachMovie(“mask”, “mask1_mc”, 2); // mask
// image_mc.setMask(mask_mc);
_root.clip1_mc.photo_mc.setMask(_root.clip1_mc.mask1_mc);
_root.clip1_mc.mask1_mc._x = -200;
[/AS]