Hi,

I've one website where I always get the following errors when enabling any synchronize option. Other websites work well. Any hints what could cause this error?

Warning: array_flip(): Can only flip STRING and INTEGER values! in DrupalDefaultEntityController->load() (Zeile 178 von /mnt/webk/e0/54/52227654/htdocs/_drupal/includes/entity.inc).
Notice: Trying to get property of non-object in file_field_presave() (Zeile 220 von /mnt/webk/e0/54/52227654/htdocs/_drupal/modules/file/file.field.inc).
Notice: Undefined property: stdClass::$uri in file_save() (Zeile 566 von /mnt/webk/e0/54/52227654/htdocs/_drupal/includes/file.inc).
PDOException: SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'field_file_display' cannot be null: INSERT INTO {field_data_field_file} (entity_type, entity_id, revision_id, bundle, delta, language, field_file_fid, field_file_display, field_file_description) 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, :db_insert_placeholder_7, :db_insert_placeholder_8); Array ( [:db_insert_placeholder_0] => node [:db_insert_placeholder_1] => 57 [:db_insert_placeholder_2] => 283 [:db_insert_placeholder_3] => produkt [:db_insert_placeholder_4] => 0 [:db_insert_placeholder_5] => und [:db_insert_placeholder_6] => [:db_insert_placeholder_7] => [:db_insert_placeholder_8] => ) in field_sql_storage_field_storage_write() (Zeile 451 von /mnt/webk/e0/54/52227654/htdocs/_drupal/modules/field/modules/field_sql_storage/field_sql_storage.module).