A couple of errors showing up when importing in a blank project:
Script 'Animation' has the same name as built-in Unity component.
AddComponent and GetComponent will not work with this script.
Assets/spine-unity/SkeletonUtility/SkeletonUtilityBone.cs(98,35): error CS0103: The name `GetComponentInParent' does not exist in the current context
Oh, right. Did a quick Google and GetComponentInParent only works from Unity 4.5 onwards. So there's that.