error 3709 in access 2000

[louis]

I open a form and use docmd to search the record. It was
found and shown. But wheneven I activate the form (any)
field, the error message is showing up.

I try to use recordset to find this record and then use
rst.delete or rst.edit/rst.update to overwrite it. But
error is shown again when it steps to rst.delete or
rst.update.

Please advise how to get rid of this record.

Thank you,