Unable to list item. Input data for tag <Item.ShippingDetails> is invalid or missing. Please check API documentation.
This means that a shipping service hasn't been selected for that item.
You'll need to open the item using the Edit function and scroll down to Shipping Details and select the appropriate service.
You should then make sure your services are setup in your eBay settings as well so that you won't incur this error again.
NOTE: Global means you're shipping it to eBay and they will ship that item to anyone in the world you've specified.
International means you're shipping the item yourself to the person in another country.