This quest was marked obsolete by Blizzard and cannot be obtained or completed.
Travel to the four Emerald Dream portals in Azeroth and collect a Fragment of the Nightmare's Corruption from each. Return to Keeper Remulos in the Moonglade when you have completed this task.
You must travel to the four dream portals of Azeroth. From each you must draw a fragment of the Nightmare's corruption. The dragonkin that inhabit these areas will hold such fragments. Return to me when you have gathered these fragments.