I don't have a Regal Bread Machine but have read that this problem could be because of a window in the top of the machine that allows heat to escape. All you need to do is fold a piece of aluminum foil and place it over the window of you machine this will help it retain the heat to cook the top of the loaf. You may want to try a different flour. I only use King Arthur Flours, they have a special for bread machines that always makes a great loaf. Check them out at www.kingarthurflour.com they may even have some suggestions.
Good Luck with your bread machine!