ToME: the Tales of Maj'Eyal

Using windows.

Casting Arcane Eye 5 in the Sandwurm Lair resulted in the game freezing and flashing black.
Log file contains this error message about 100 times:
Lua Error: /engine/interface/ActorTemporaryEffects.lua:102: attempt to index a nil value
At [C]:-1 __index
At /engine/interface/ActorTemporaryEffects.lua:102 setEffect
At /mod/class/Player.lua:392
At [C]:-1 calc_circle
At /mod/class/Player.lua:385 playerFOV
At /mod/class/Game.lua:1077 updateFOV
At /mod/class/Game.lua:1087 displayMap
At /mod/class/uiset/Minimalist.lua:1764 display
At /mod/class/Game.lua:1156

Edit: It doesn't like it being cast through walls.