This indicates that eCard Selections data element is corrupt.  Perform the following procedure to resolve this issue.

Note: Decide if you want to edit the existing donation form (unpublish a published form) or create a copy of the existing donation form.  If you create a new copy and edit it, you can unpublish the existing form and publish the copy later.  This latter method ensures a more seamless transition while resolving this issue.
  1. Remove the eCard Selections data element from the donation form and click Save.
  2. Add the eCard Selections data element back to the donation form and click Save.
  3. Highlight the eCard Selections data element and click Save Order and Add Selected.
  4. Click Edit Data Element and select the eCards to add to the donation form.
  5. Ensure that all of the eCard settings are correct and click Save.