That is a beautiful quilt and I love the blue and yellows together.
Mary.....are the puckers or ripples in the triangle section on the bottom left and bottom right of the picture you posted? Is that the area that you had the problem with. The large center square looks like it's lying flat without any ripples.
check out the previous postings about this pattern. Kitty Yates, Stitchin4Fun, Debra Mc, Diamonds, ccbear66 and Quilting Aggi all were ordering it. Maybe they can give you some insight into the problem.....but don't give up on it or let it get the best of you.
http://www.quiltingboard.com/posts/list/4089.page