I Followed the video exactly and got this when try to load the dragon example in the lastest build of Unity:

Error reading skeleton JSON file for skeleton data asset: DragonSkeletonData
Sprite not found in atlas: logo (region)
  at SpriteCollectionAttachmentLoader.NewAttachment (Spine.Skin skin, AttachmentType type, System.String name) [0x0007e] in C:\PROJECTS_UNITY_4\2D_TK_Spine_Tests\Assets\Spine\spine-tk2d\Assets\Spine\SpriteCollectionAttachmentLoader.cs:67 
  at Spine.SkeletonJson.ReadAttachment (Spine.Skin skin, System.String name, System.Collections.Generic.Dictionary`2 map) [0x0005a] in C:\PROJECTS_UNITY_4\2D_TK_Spine_Tests\Assets\Spine\spine-csharp\src\SkeletonJson.cs:202 
  at Spine.SkeletonJson.ReadSkeletonData (System.IO.TextReader reader) [0x003ae] in C:\PROJECTS_UNITY_4\2D_TK_Spine_Tests\Assets\Spine\spine-csharp\src\SkeletonJson.cs:160 
  at SkeletonDataAsset.GetSkeletonData (Boolean quiet) [0x000b7] in C:\PROJECTS_UNITY_4\2D_TK_Spine_Tests\Assets\Spine\spine-tk2d\Assets\Spine\SkeletonDataAsset.cs:76 
UnityEngine.Debug:Log(Object, Object)
SkeletonDataAsset:GetSkeletonData(Boolean) (at Assets/Spine/spine-tk2d/Assets/Spine/SkeletonDataAsset.cs:78)

Totally Lost on how to fix it!!