Adjacent Movieclips "Jiggle"?

Here’s my example SWF:

http://www.swfcabin.com/open/1265831402

When it loads, all the sprite instances are lined up pretty well (also when you zoom out all the way they are re-aligned correctly). However, when you drag the board around (shift + click/drag), you can see that they are jostled a little bit, creating weird lines of space between them. This occurs at every zoom level.

I’m using a VCam to simulate the zooming, and the tiles are part of a parent container that uses start/stopDrag(). Is there a better way to go about dragging around the tile groups? Maybe I’m just doing something completely wrong all together that’s messing everything up.

Code is ready to post, just request a certain section and its yours.