Last night I was unable to post due to bad lag problems, but heres what I wanted to say:
Go back to your trainer and talk to him, maybe he can give you a new one.
If that doesnt work, abandon the quest, if item is still in backpack, delete it, and take quest again.
So... basically what everyone else said already... meh.
I really didnt want to not respond with the idea in my mind already.