Darkfire / flame weapon are reported on the character sheet yet deal no damage when attacking a target. I assume it's a bug since this spell functions on Monk gloves (and even throwing weapons for all you ranged weapon types! :O )
I'm pretty sure Darkfire doesn't work on thrown weapons, tried to do it on a Cleric when I discovered MW did. Flame certainly works on Polymorph creature weapons at least. I've had Transmuters be buffed with it by another PC, to take on quests.
Does your attacks section of the character sheet look like (random example)
QuoteAttack Bonus: +4
Damage: 1-3+1
or is it like
QuoteAttack Bonus: +4
Damage 1: 1-3+1
Damage 2: 1-3+1
Damage 3: 1-6+2
The reason it doesn't look like it works on some summons, as an example of natural weapons, is because of the latter option being multiple attacks. If it's the first, well, maybe it's just a problem with the claws not working right. If it is the latter then only one of those multiple attacks has flame weapon. The others do not, and when in combat it randomly selects one of the attack types. So it might randomly decide that your bite attack (damage type 3 in this example) has flame weapon, but two claw attacks do not, so only 1/3 of the attacks get flame weapon bonus.
No, it's not the multiple attacks, and even if it were (bite, claw, claw) it would still work on the attack that was enchanted but not the other two
Eww. It does sound like there is some sort of bug on the creature weapon property or something then. *pouts*
Mort said its a bug that darkfire even works on "natural weapons"