Broken Spokes

I have a pair of Cane Creek Areohead wheels. After a few months of use, I noticed they started creaking when out of the saddle. I figured the spokes were loosening up during the wear in period so I tightened the nipples 1/2 turn. It seemed to stop the creaking. However 1 month later (yesterday) I broke a spoke. It was on the rear drive side of the wheel. I called Cane Creek and they said that it should not have happened and sent out a spoke kit.

I weigh about 225lbs, 6'4" and really like to hammer the hills. What does everyone think? Am I too heavy/hard on these type of wheels? They are radially laced with a cross on the drive side rear. Should I go back to the old school 3 cross custom builds?