Humidity. Not humid enough when it mattered, so the snake is shedding in pieces.
Soak him in lukewarm water for about fifteen minutes, then place him back in the cage. Most of the shed should come off.
Try checking into ways to bump up the humidity. Some methods that I've tried and had work for me with aquariums include coving the screen lid, putting a damp towel between the cover and the screen, using cypress mulch or cocosoft bedding, placing moss in hides and throughout the cage and misting that often enough to keep it moist, and misting the entire cage every day or every other day.
Good luck!
~jenny
-----
"Polysyllabism in no way insures that what you're saying is actually worth being heard." - Blake (an e-friend of mine)
"I have never made but one prayer to god, a very short one: "O lord, make my enemies ridiculous." And he granted it." - Voltaire