A relationship type of "Variation" was provided for an item with no VariationTheme.
If you submit a tab-delimited inventory files, this error occurs when you provide a RelationshipType value for a child product but omit a VariationTheme value. Child products with a RelationshipType must also have a VariationTheme. To resolve this error, resubmit your inventory file with a valid VariationTheme for the child products.
If you post relationships feeds (XML), this error occurs when one of the SKU values you
provide in a Relationship element was not previously assigned a VariationTheme in a product
data feed. To resolve this error, you should do the following: