Unable to add field to Article content type

Use case: I want to be able to link a node to a forum entry. I've been through all the configuration, but when I added a ANR field to the "Article" content type, I get this error message and cannot edit the field parameters.

Notice: Trying to get property of non-object in autocreate_field_widget_form() (line 188 of /Users/joelguesclin/Sites/acquia-drupal/sites/all/modules/autocreate/autocreate.module).
PDOException: SQLSTATE[HY000]: General error: 1366 Incorrect integer value: '' for column 'sticky' at row 1: INSERT INTO {forum_index} (nid, title, tid, sticky, created, comment_count, last_comment_timestamp) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6); Array ( [:db_insert_placeholder_0] => 5 [:db_insert_placeholder_1] => Forum topic [:db_insert_placeholder_2] => 1 [:db_insert_placeholder_3] => [:db_insert_placeholder_4] => 1366218218 [:db_insert_placeholder_5] => 0 [:db_insert_placeholder_6] => 1366218218 ) in forum_field_storage_pre_insert() (line 541 of /Users/joelguesclin/Sites/acquia-drupal/modules/forum/forum.module).