Hypersmurf
Moderatarrrrh...
jabberwocky said:If this is the case, then you do 1d6 extra fire damage.
You don't; the flaming weapon does. "A flaming weapon deals an extra 1d6 points of fire damage on a successful hit."
And the flaming weapon is a whip, which "deals no damage to any creature with an armor bonus of +1 or higher or a natural armor bonus of +3 or higher".
Or would you argue that a flaming sap does nonlethal-fire damage?
The sap isn't in the SRD, and I'm away from my PHB, but probably

I'd certainly say that the fire damage dealt by a Merciful Flaming Longsword is nonlethal - is that so different?
-Hyp.