For 10% extra credit and that extra bit of satisfaction:

Remove the unique constraint from dbi_errors:
  alter table dbi_errors disable constraint de_form_id_check_id_un;

Insert a tuple or several tuples which violate this constraint.  At
least one of them should be for a form that is approved.

Write a query that returns the form_ids of any forms that have been
approved but have more than one entry in dbi_errors with the same
check_id.