Try:
local combat = createCombatObject()
setCombatParam(combat, COMBAT_PARAM_TYPE, COMBAT_FIREDAMAGE)
setCombatParam(combat, COMBAT_PARAM_EFFECT, CONST_ME_HITBYFIRE)
setCombatParam(combat, COMBAT_PARAM_DISTANCEEFFECT, CONST_ANI_FIRE)
setCombatParam(combat, COMBAT_PARAM_CREATEITEM, 1492)
local...