Dynamic Image Problems w/ a Mask+Tween

I’m attempting to dynamically load an image into a movie clip and then have that clip tween across the stage. The problem I’m seeing is that the mask on top of the image layer is affecting this in a negative way. I’m seeing at the minimum a “flicker” when the image gets to its final resting place, though depending on how I load the image into the clip, sometimes it disappears altogether.

If this makes sense to anyone, is it possible there’s a bug in Flash MX 2004 where a clip can “lose” track of its instance name after a tween if there’s a mask also tweaning above it? It seems to think it’s a totally different instace once it stops, but if I delete the mask layer everything is fine (outside of not masking where it needs to mask).

If this should be posted to a more appropriate forum, please let me know.

thanks,
-andy