IndexError

Level 1 of the Dungeon
(0, 0, D:1)
  a +0 club
(15, 2, D:1)
  9 stones
(21, -2, D:1)
  a +0 leather armour
(26, 2, D:1)
  a +0 short sword
  a +0 dagger
  a +0 club
(29, 5, D:1)
  a +0 club
(33, 18, D:1)
  a +0 club
(40, -1, D:1)
  a +0 whip
(40, 26, D:1)
  a +2 heavy quarterstaff
(52, 13, D:1)
  a +0 whip
  4 stones
(53, 22, D:1)
  a +0 whip

Level 2 of the Dungeon
(11, 15, D:2)
  a +0 leather armour
(30, -5, D:2)
  a +0 club
(33, -6, D:2)
  a +0 ring mail
(49, -3, D:2)
  a +0 dagger
(54, -23, D:2)
  a +0 ring mail

Level 3 of the Dungeon
(2, 12, D:3)
  a scroll of teleportation
(3, 0, D:3)
  a +0 flail
  a +0 chain mail
  a +0 kite shield
(10, -11, D:3)
  a +0 dagger
(16, 5, D:3)
  a +0 ring mail
(20, -6, D:3)
  a +0 chain mail
(25, -7, D:3)
  a +0 mace
(26, 0, D:3)
  3 stones
(26, 7, D:3)
  a +0 dagger
(27, -14, D:3)
  a +0 dagger
(27, -6, D:3)
  a +0 whip
  an orc skeleton
(30, -3, D:3)
  a +0 club
  a +0 ring mail
  an orc skeleton
(32, 5, D:3)
  a +0 dagger
  8 poisoned darts
(33, -1, D:3)
  4 stones
(33, 0, D:3)
  a +0 sling
  a +0 dagger
  a goblin corpse (skeletalised by now)
(35, 9, D:3)
  an adder corpse (skeletalised by now)
(41, -20, D:3)
  a +0 hand axe
(47, 6, D:3)
  a +0 club
  a goblin skeleton
(48, 19, D:3)
  a +0 dagger
(51, 17, D:3)
  a hobgoblin corpse (skeletalised by now)
(52, 3, D:3)
  a +0 robe
(53, 19, D:3)
  a bat corpse (skeletalised by now)
(54, 13, D:3)
  a rat corpse (skeletalised by now)

Level 4 of the Dungeon
(0, 0, D:4)
  a throwing net
(1, -7, D:4)
  a +0 flail
  a gnoll corpse
(2, -8, D:4)
  a +0 dagger
  a goblin skeleton
(2, -7, D:4)
  a jackal skeleton
(2, -6, D:4)
  a jackal skeleton
(2, 4, D:4)
  a +0 club
  a gnoll corpse
(3, -5, D:4)
  a +0 halberd
  a gnoll corpse
(3, 5, D:4)
  a ring of willpower
(4, -4, D:4)
  a +0 halberd
(4, 0, D:4)
  a throwing net {=f, !d}
(6, -11, D:4)
  a +0 spear
  a gnoll corpse
(7, -8, D:4)
  a +0 leather armour
(9, -12, D:4)
  a ball python skeleton