This message is occurring because Gift subtype has been made a required field at Config > Fields > Gifts.

Try the following steps until resolved. Validate the batch after each step to see if it addressed the exception.
  1. Ensure the Gift subtype field is added at Tools > Edit batch set-up > Fields tab. Once the field is added, enter a value.
  2. Place the cursor on the row. Go to Gift > Match to review MG Pledges. Either delete the MG Pledge or open to add a Gift Subtype to the MG Pledge.
  3. Delete the row and re-enter the gift.
  4. If needed, return to Config > Fields > Gifts to make Gift Subtype not required temporarily.