Quote Originally Posted by Jojo00182 View Post
You will also have to rename/remove the vanilla animations folder(specificly pack/skeleton.pack/.idx) or the game will look there for animations and crash.
Quote Originally Posted by The Bat file section
It will first rename the game's animation folder, then start the mod and after 20 seconds reverse the folder renaming which is ample time for the files to be generated.
'the game' = vanilla

I have now updated to: "...the original game's ('vanilla') animation folder..."