In cake 1.2 when setting the "displayable" fields of the model in question, use the related model's name.

class JournalController extends AppController {
...
var $paginate = array(
                'Journal' => array(
                        'limit' => 25,
                        'fields' => array(
                                'Journal.id',
                                'Incident.id',
...

Not 'Journal.incident_id'