How to play animation on an NPC?

local animControl = Instance.new("AnimationController", game.Workspace.Hacker)
local animation = Instance.new("Animation", animControl)
animation.AnimationId = "http://www.roblox.com/asset/?id=498797940"
local animTrack = animControl:LoadAnimation(animation)
animTrack:Play()

Hacker is the NPC Model. He has a HumanoidRootPart, Humanoid, and every body parts a normal human has. The animation is purely made by me, and I don't know why the animation does not play on an NPC while it worked on players.

If you just copy and pasted the localscript, that is wrong. You need a server side script(a normal Script)

http://goo.gl/vOu1NX