Thanks Jasmin,
My xfaForm variable points to a PDF.
The log shows errors - I've pasted a few sections that seem useful below...
2007-11-16 14:01:12,500 INFO [STDOUT] Nov 16, 2007 2:01:12 PM com.adobe.idp.jobmanager.ejb.JobManagerBean completeJob
SEVERE: JobManagerBean:completeJob:exception:Cannot coerce object: 514 of type: java.lang.Long to type: class com.adobe.idp.taskmanager.form.impl.xfa.XFARepositoryFormInstance
2007-11-16 14:01:12,500 ERROR [org.jboss.ejb.plugins.LogInterceptor] RuntimeException in method: public abstract java.lang.Object com.adobe.idp.dsc.transaction.impl.ejb.adapter.EjbTransactionCMTAdapterLocal.doSupports(com.adobe.idp.dsc.transaction.TransactionDefinition,com.adobe.idp.dsc.transaction.TransactionCallback) throws com.adobe.idp.dsc.DSCException:
ALC-DSC-000-000: com.adobe.idp.dsc.DSCRuntimeException: Internal error
2007-11-16 14:01:12,500 INFO [STDOUT] Nov 16, 2007 2:01:12 PM com.adobe.idp.event.notification.NotificationManagerImpl deliverNotificationToService
SEVERE: Notification could not be delivered to registered subscriber. Reason: Internal error.
2007-11-16 14:01:12,500 INFO [STDOUT] Nov 16, 2007 2:01:12 PM com.adobe.idp.event.notification.NotificationManagerImpl setNotificationDeliveryFailure
INFO: Attempting to disable the notification after delivery.
2007-11-16 14:01:12,515 INFO [STDOUT] Nov 16, 2007 2:01:12 PM com.adobe.idp.event.notification.NotificationManagerImpl setNotificationDeliveryFailure
INFO: Attempting to disable the notification after delivery.
2007-11-16 14:01:12,515 INFO [STDOUT] Nov 16, 2007 2:01:12 PM com.adobe.idp.event.util.EventDBHelper getActiveEventByPrimaryKey
INFO: Event with id 552 is already disabled, EventService will not deliver notification.
2007-11-16 14:01:12,515 INFO [STDOUT] Nov 16, 2007 2:01:12 PM com.adobe.idp.event.notification.NotificationManagerImpl updateEventStatus
INFO: Event with id 552 is already inactive.Event instance with id 552 is inactive for TaskCompleted