Instrument of agony - a few questions about the spell

[Just a Mort]

Spell description as follows:

Range touch
Target weapon touched
Duration 1 minutes/level
Saving Throw Will negates (harmless, object), see text; Spell Resistance yes (harmless, object), see text

You cause a weapon to exude a palpable aura of divine fury. While wielding this weapon, a creature gains a +2 morale bonus on Intimidate checks. When an attack made using the targeted weapon hits, the wielder can spend a free action to discharge the effect to inflict agony on the creature the weapon hit. If that creature has spell resistance, it applies against this effect. If the creature fails a Will save, it is nauseated for 1d4+1 rounds. If it succeeds at the saving throw, the creature is instead sickened for 1 round. The sickened condition created by the instrument is a mind-affecting effect.

a) Can it be cast on a natural weapon (i.e a bite)?

b) Can it be cast on a ranged weapon(i.e a bow)? With all arrows firing from that bow given the ability to discharge agony on hit?

c) With Threnodic Spell metamagic - it affects undead even though they are usually immune to nauseated condition?
Under this clause: Immunity to death effects, disease, paralysis, poison, sleep effects, and stunning.(undead traits)

d) When used with persistent spell metamagic - the creature that gets hit has to make 2 saves to prevent from being nauseated?

e) Does empower spell increase the duration of nauseation on failed save?

[Dennis Baker]

A) Yes
B) Yes, but the ability can only be discharged once.
C) Nauseated isn't a death effect, disease, poison, sleep effect, or stunning.
D) Yes
E) Yes

[AvalonXQ]

I don't believe undead are immune to the nauseated and sickened conditions.

If I'm correct, a threnodic instrument of agony should work as normal against undead.

[Just a Mort]

Why only once for a ranged weapon? The duration is 1 min/level. If it were cast on a melee weapon would you get to discharge agony on successful hit until duration of spell end? ie - if its cast on a fighters great sword and he hits the same monster 3 times in the combat round - he discharges agony 3 times so the monster has to major 3 will saves?

[Menelmacar]

Usually discharging a spell means the spell is gone afterwards (with all it's passive effects). For most of these spells in the duration there is something like "1 Round/Level or until discharged". It's strange this isn't found here but since it's a Level 2 spell I'd certainly rule it that way. You discharge it once, the whole effect is gone.