The error for FBA_INBOUND_CARTON_016 indicates that you have more items in your Seller Central Working Shipment than you do in your InventoryLab Box Content Information. This can happen if you have unassigned or decreased the quantity of the items you are sending in within the InventoryLab Box Content section, but have not yet made the same actions within the Working Shipment under Review and Modify Units in Seller Central.
To fix this, make sure the quantities of your items in Seller Central match the quantities of the items you have assigned in InventoryLab and send the box content information again by clicking the 3 horizontal lines to the right of the shipment you need to resend and select “Box Content Information”.
Then, click the "Transmit Updated Boxes" button in the lower right hand corner.
*Note: You would assign a quantity of 0 in InventoryLab if you have deleted the item from your shipment completely in Seller Central as outlined here.