IndexError

Level 1 of the Dungeon
(0, 0, D:1)
  a rat skeleton
(0, 19, D:1)
  a +0 leather armour
(5, 4, D:1)
  a hobgoblin skeleton
(9, 2, D:1)
  a +0 dagger
(11, 11, D:1)
  a bat skeleton
(11, 19, D:1)
  a +0 short sword
(13, 17, D:1)
  a +0 short sword
  a kobold skeleton
(20, 32, D:1)
  a hobgoblin corpse (skeletalised by now)
(28, 4, D:1)
  a hobgoblin skeleton
(29, 4, D:1)
  a ball python skeleton
(30, 30, D:1)
  a ball python corpse (skeletalised by now)
(33, -8, D:1)
  a +0 ring mail
(35, 13, D:1)
  a +0 ring mail
(41, 24, D:1)
  a quokka corpse (skeletalised by now)
(43, 35, D:1)
  a +0 sling
(45, -21, D:1)
  a jackal corpse (skeletalised by now)
(45, -17, D:1)
  a +0 short sword
(46, -19, D:1)
  a jackal corpse (skeletalised by now)
(50, 39, D:1)
  a frilled lizard corpse (skeletalised by now)
(52, -9, D:1)
  a frilled lizard skeleton
(56, -4, D:1)
  a +0 dagger
  a goblin skeleton
(57, 32, D:1)
  a bat corpse (skeletalised by now)
(61, 25, D:1)
  a ball python corpse (skeletalised by now)

Level 2 of the Dungeon
(0, 0, D:2)
  an adder corpse (skeletalised by now)
(1, 5, D:2)
  a rat corpse (skeletalised by now)
(4, 4, D:2)
  a +0 chain mail
(4, 21, D:2)
  a rat corpse (skeletalised by now)
(20, -1, D:2)
  a +0 ring mail
(22, 12, D:2)
  4 stones
(24, 5, D:2)
  5 stones
(24, 9, D:2)
  a frilled lizard corpse
(30, 9, D:2)
  a giant cockroach corpse
(31, 6, D:2)
  a frilled lizard corpse
(38, 11, D:2)
  a +0 leather armour
(39, -3, D:2)
  a +0 dagger
  4 stones
(43, 2, D:2)
  2 potions of lignification
(44, 8, D:2)
  a ball python corpse

Level 3 of the Dungeon
(0, 0, D:3)
  an amulet of regeneration
(1, 4, D:3)
  a bat corpse
(2, 2, D:3)
  a staff of alchemy
  (unseen)
(4, 3, D:3)
  a rat corpse
(8, 8, D:3)
  a +0 flail
(9, 2, D:3)
  9 gold pieces

Level 4 of the Dungeon
(0, 0, D:4)
  a potion of degeneration
(10, -13, D:4)
  a quokka corpse
(11, -4, D:4)
  4 stones