Join / link table / error

Hi,

When NOT setting a value when updating a record, I get the following error:

Notice:  Undefined index: tblExerciseEquipment in <b>/Users/nathan/Sites/xxx.com/functions/datatables/Editor/Join.php</b> on line <b>474</b>

I don't get the error when selecting (checkbox) one or more items.

Please point me in the right direction.

       		Join::inst( 'tblExerciseEquipment', 'array' )
            ->join(
                array( 'EID', 'f_EID' ),
                array( 'EEquipmentID', 'f_EEID' ),
                'tblExercisesXEquipment'
                )
               //->set(false)
            ->field(
                Field::inst( 'EEquipmentID' )->validator( 'Validate::required' ),
                Field::inst( 'EquipmentName0' )
            )