When trying to demote a group of nodes from the front page, the following error occurs:

PDOException: SQLSTATE[HY000]: General error: 1366 Incorrect integer value: '' for column 'status' at row 1: UPDATE {signature_forum_post} SET type=:db_update_placeholder_0, delta=:db_update_placeholder_1, status=:db_update_placeholder_2 WHERE ( (type = :db_condition_placeholder_0) AND (delta = :db_condition_placeholder_1) ); Array ( [:db_update_placeholder_0] => node [:db_update_placeholder_1] => 678 [:db_update_placeholder_2] => [:db_condition_placeholder_0] => node [:db_condition_placeholder_1] => 678 ) in _signature_forum_object_update() (line 936 of /home/[site]/public_html/sites/all/modules/signature_forum/signature_forum.module)

Workaround is to disable module, perform bulk operation and re-enable.

Any ideas much appreciated... thanks!