Call Robyn (sp?) at ProExoctics and ask her what they were feeding him and the size of the prey, how he was housed, etc.
Joanna gave you a very good summary of what to check . . .
Good luck
Robyn is a guy!
I also agree, go over Joanna's post and check everything. I also feed no larger than a small rat (40-50 grams or 3-5 weeks old) to any of my ball pythons, and my largest is over 3000 grams. A year old snake does not need a medium, large or jumbo rat.