ToME: the Tales of Maj'Eyal

pressing 'm' gives:

Lua Error: /data/talents/spells/advanced-golemancy.lua:80: attempt to index local 'golem' (a nil value)
At [C]:-1
At /data/talents/spells/advanced-golemancy.lua:80 getGolemDamage
At /data/talents/spells/advanced-golemancy.lua:130 info
At /engine/interface/ActorTalents.lua:78 info
At /mod/class/Actor.lua:1658 getTalentFullDescription
At /engine/dialogs/UseTalents.lua:179 generateList
At /engine/dialogs/UseTalents.lua:40 init
At /engine/class.lua:64 new
At /engine/interface/ActorTalents.lua:524 useTalents
At /mod/class/Game.lua:913 f
At /mod/class/Game.lua:681 ?
At /engine/KeyBind.lua:202