Centered pop-up tutorial problem

I attempted the pop up tutorial last night (alright, I cut and pasted code…and then changed a couple of variables…) but it’s not working quite right.

I’ve set the new window size to match the dimensions of my movie, but when the window opens the movie is off center. Nothing I have tried has fixed that problem. I’m sure it’s a simple fix; I just can’t find it.

Thanks for the help.