The eBay errors messages are very confusing. In other words, this eBay error message: "The tags Style is/are disabled as Variant" means that word "Style" cannot be used. In different eBay categories, there might be different words.
Please check the product you want to list. It has Style as an label for options (either for custom options or for associated products). When you list a product with variations, eBay system detects this word and returns error, as it has list of reserved words in some eBay categories which can not be used.
To avoid this error, the option label should be changed. i.e. Style -> Product Style.
Then eBay system will not consider it as reserved word.