Cannot register event participant from admin menu

We are on CiviCRM 4.4.3 / Wordpress

We are trying to register event participants. We have both a user registration form (front end) and obviously a way to register participants from the Admin menu.

When you register from the front end it works.. But, if you use the "Events -> Register Event participant" option from the backend - it does not.

In one case (the working case), it is using the event_id to look up the constraint
In the other case (backend - non-working case), it appears to be using the participant's id to look up a foreign key constraint against the events table and the IDs don't match

If I go to the admin menu and try to register an event participant from there, i get this error:

Array
(
[callback] => Array
(

=> CRM_Core_Error
[1] => handle
)
=> -3
[message] => DB Error: constraint violation
[mode] => 16
[debug_info] => INSERT INTO civicrm_value_conference_registration_12 ( participant_2_first_name_33,additional_participants_35,additional_conference_participan_41,entity_id ) VALUES ( '','','',712 ) ON DUPLICATE KEY UPDATE participant_2_first_name_33 = '',additional_participants_35 = '',additional_conference_participan_41 = '' [nativecode=1452 ** Cannot add or update a child row: a foreign key constraint fails (`fpwr_civi_433/civicrm_value_conference_registration_12`, CONSTRAINT `FK_civicrm_value_conference_registr_91ad01a1a86df0c7` FOREIGN KEY (`entity_id`) REFERENCES `civicrm_event` (`id`) ON DELET)]
[type] => DB_Error
[user_info] => INSERT INTO civicrm_value_conference_registration_12 ( participant_2_first_name_33,additional_participants_35,additional_conference_participan_41,entity_id ) VALUES ( '','','',712 ) ON DUPLICATE KEY UPDATE participant_2_first_name_33 = '',additional_participants_35 = '',additional_conference_participan_41 = '' [nativecode=1452 ** Cannot add or update a child row: a foreign key constraint fails (`fpwr_civi_433/civicrm_value_conference_registration_12`, CONSTRAINT `FK_civicrm_value_conference_registr_91ad01a1a86df0c7` FOREIGN KEY (`entity_id`) REFERENCES `civicrm_event` (`id`) ON DELET)]
[to_string] => [db_error: message="DB Error: constraint violation" code=-3 mode=callback callback=CRM_Core_Error::handle prefix="" info="INSERT INTO civicrm_value_conference_registration_12 ( participant_2_first_name_33,additional_participants_35,additional_conference_participan_41,entity_id ) VALUES ( '','','',712 ) ON DUPLICATE KEY UPDATE participant_2_first_name_33 = '',additional_participants_35 = '',additional_conference_participan_41 = '' [nativecode=1452 ** Cannot add or update a child row: a foreign key constraint fails (`fpwr_civi_433/civicrm_value_conference_registration_12`, CONSTRAINT `FK_civicrm_value_conference_registr_91ad01a1a86df0c7` FOREIGN KEY (`entity_id`) REFERENCES `civicrm_event` (`id`) ON DELET)]"]
)

It appears that its using the participants entity_id, not the events entity_id - and the foreign key constraint / relationship is with the event table

Workaround is to register people from the front end civievent forms - but it would be much easier and better if this was fixed.