Richard,

I hate to be the bearer of bad news, but cracking is not good. Usually it comes from applying too many coats too fast. The best way to eliminate the problem is to sand the cracks completely out and reprime. Thats not the only way, but it is by far the best way. I'm sorry about that! I suppose the best advice that I can give you is to lighten up on the heavy coats. Light to medium coats while letting each coat flash off before the next coat should give you satisfactory results. Just don't give up. Keep trying and you will get it. If it makes you feel any better, my first paint job ran off on to the floor.