From the error, I only understood that I need to give an ID to the artifact. All IDs are in the file from the developers, which I don't have. But I don't quite understand what to do with the monster.
function footmanFunction(hero)
Trigger(OBJECT_TOUCH_TRIGGER, 'footman', nil);
GiveArtefact(hero, itemId);
end;
Trigger(OBJECT_TOUCH_TRIGGER, 'footman', 'footmanFunction');