Moving scaled graphic
I think your problem could be you've selected or moved the reference point for your graphic. At the tool bar at the top of the screen there is a little grid of 10 dots, usually the centre spot is selected meaning any adjustments will scale from the centre, but if you've moved to one of the side dots (or even further) that's where your scale will start from, hence the graphic moving. I'm using a newer version of Illustrator (CS4) and can't remember if it's the same on your version, but would guess this is the problem. Reset the dot to the centre, fixed!