Duplicate take error on Meta Creation

[mwillson]

Thought I followed the instructions fairly accurately for Meta, but I get this error every time I try to save a new meta prefab:

NullReferenceException: Object reference not set to an instance of an object M8.Animator.AnimatorDataEdit.DuplicateTake (M8.Animator.AMTakeData dupTake, Boolean includeKeys, Boolean addCompUndo) (at Assets/MateAnimator-master/Editor/AnimatorDataEdit.cs:298) M8.Animator.AnimatorDataEdit.MetaSet (M8.Animator.AnimatorMeta newMeta, Boolean copyTakes) (at Assets/MateAnimator-master/Editor/AnimatorDataEdit.cs:392) M8.Animator.AnimatorDataInspector.OnInspectorGUI () (at Assets/MateAnimator-master/Editor/AnimatorDataInspector.cs:192) UnityEditor.InspectorWindow.DrawEditor (UnityEditor.Editor editor, Int32 editorIndex, Boolean rebuildOptimizedGUIBlock, System.Boolean& showImportedObjectBarNext, UnityEngine.Rect& importedObjectBarRect) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1235) UnityEditor.DockArea:OnGUI()

I've tried various object hierarchies and they all seem to result in this. Maybe part of it, maybe a symptom down the pipeline, but: target paths in the track data are not being set. Hopefully that's helpful info :)