- There may be a Validation rule defined on one or more of the fields
in the table, and some value which is coming from the Append violates
that rule.
- There may be a Table Validation rule among the table's properties
which is being violated.
- You may have a required field for which no value is being appended.
- You may have a relationship to some other table, and you're
attempting to add a foreign key to a nonexistant record.