Can't Reposition my movie!

So, my problem is that I have a movie clip placed in my frame, and inside that movie clip is some actionscript that loads another random movie clip into it and plays. That part is all working fine. But the problem is, is that the movie clip shows up in the top right, and not in the center like it should be. So what can I do to reposition it?

My Code:

i = Math.ceil(Math.random()*20);
i++;
_root.attachMovie("com_"+i, "clip"+i, 2);
trace(i);

check the registration point inside of your movie clip that loads the clips, It is probably in the top right.