That problem is not related to your save.
You started an older version of the game, but use new json data. Specifically the materials array in the item definitions used to contain exactly 2 materials, but the current version can handle any number of materials. Therefor the current definition of cured hide contains a materials array with only one entry. This loads fine with the current version, but older versions can not handle such a small array.
You should use a more current version.