Why wont this walking animaton work>?

I want the animation to play when you walk, but it isnt working

Blue squiggly line under humanoid on line 6

local animation = Instance.new("Animation")
animation.AnimationId = "http://www.roblox.com/Asset?ID=########"

game.Workspace.Player.Humanoid.Running:connect(function(speed)
    if speed == 16 then
  		local animTrack = Humanoid:LoadAnimation(animation)
animTrack:Play()
end
end)