[CS3] Blinking bitmaps moved by AS

Hi everyone, and sorry for my english.

I have a layered world, made by some several giant bitmaps (3000x700) inside movieClips. I programmed a small functionalitiy to move them against mouse position in different speeds to give this worlds a sense of depth, and repositioning them once a top position is reached to make this a neverending movement.
Everithing is working fine except that all bitmaps are “blinking” while moving. I tryied smoothing from library but its not entirely solving it, either cacheAsBitmap… maybe im getting a little obsesed, but i can still see the blinking. Is this unavoidable? Does someone knows how to reduse this effect over bitmaps (or a better way to achieve this).