This quest was marked obsolete by Blizzard and cannot be obtained or completed.
You've certainly earned my trust, <name>, but you may need to continue to earn the trust of my untrusting tribe. There is something you can do to earn that trust.
The Winterfall are known to carry spirit beads to ward against foul spirits. These beads have clearly failed in their purpose, as the Winterfall themselves are the agents of corruption. Bring to me these spirit beads from fallen Winterfall furbolgs; for every set of five you bring me, you will earn recognition amongst the Timbermaw.