I believe what this is telling you is that if you are using a polygon as your input (which is how the wizard creates your spaces), your area is pretty much set in stone. The only way I have ever changed the area of a space or zone is to go back into the wizard. You can try to play with the polygons but It will more than likely be a lot more trouble than redoing your detailed edit work. Id just suck it up and re-enter the wizard. If your not trying to change your space area in detail mode and your getting this error, then I don't have a clue. Maybe try restoring your space areas to default (green) if any of them are red. Good luck.