Why does my frost-free freezer keep icing over in the bottom drawer?

Roughly every month I have to chisel away a huge slab of ice that builds up underneath, and surrounding, the bottom drawer of the freezer compartment of my Hotpoint Ultima 50/50 FF. It is sometimes so severe it even pushes the drawer forward and opens the door. And sometimes water drips from the bottom of the door onto the floor. IT IS DRIVING ME MAD! Please help . . . someone . . . anyone . . .