Why does my script only work in test mode on studio and not on multiplayer servers? [UNSOLVED]

The code below is in a regular script, placed inside an NPC. The script works perfectly in test mode on studio but doesn't work in a multiplayer server, even if I'm the only person in the game.

The animation is one that I've made myself and is on my account.

wait(3)
Animation = Instance.new("Animation")
Animation.AnimationId = "http://www.roblox.com/Asset?ID=234539352" 
animTrack = script.Parent.Humanoid:LoadAnimation(Animation)

animTrack:Play()

Could anyone tell me what I need to do fix this?

Thanks.

Try putting it in a LocalScript. The animation works in a regular script because it is a server, but in a Client, you'd need a LocalScript.