Focus Pocus

I am having trouble using the autofocus in my new camera; manual focus is no problem as it does what I tell it to do, but in autofocus the focus points run riot around my viewfinder, leaping uncontrollably from one point to another. So, any suggestions from others with this model would be helpful. This is a magnolia blossom, that will look lovely for a day and then turn brown and nasty. They are beautiful when new and white though, and the smell is intoxicating. Well, it could have been the gin, of course; blame the focus problem.