Cards that have no rigged skirt make the blender plugin cause errors.

[TheMaskedMan00]

I looked into the errors and it seems that bonedrivers.py will look for the skirt bones so it can add them to a separate armature layer, but if there are no skirt bones then it will just throw an error. I think the cause is these lines
https://github.com/FlailingFog/KK-Blender-Porter-Pack/blob/master/importing/bonedrivers.py#L679-L684