1. Open the Gift batch
  2. In the Batch setup, remove any duplicate attribute fields
  3. Click Save
  4. Click Data Entry
  5. Update the gifts in the batch as needed
  6. Save the batch
  7. Commit the batch

If the batch contains corporate donations, check the OPX Corporate Donation attribute to ensure it has a Contact selected.  If not, search for and select the appropriate contact or remove the attribute from the Batch if the Contact is not known.