If an archer with the Ranged Sunder feat shoots a blunt arrow (A&EG, p. 5), can he try to Sunder with it? Or is this not possible because blunt arrows deal subdual damage, with no way to deal lethal damage?
You can (probably) try to Sunder, but it won't do any good.
Subdual damage was renamed nonlethal damage in 3.5, so I'm going of that.
Smashing an Object has this to say (under Hardness):
There's no basis to differentiate object hit points from character hit points. Nonlethal damage states:
Emphasis not even mine.
Furthermore, objects can neither be staggered nor unconscious, so keeping track of nonlethal damage on an object is pointless.
Of course, as always, you are free to houserule this particular case, since it seems to make sense. Even with Ranged Sunder you deal only half damage to objects with piercing weapons, so you might allow blunt arrows to do full damage.