D7 session error

An AJAX HTTP error occurred. HTTP Result Code: 500 Debugging information follows. Path: http://dev.example.com/batch?id=114&op=do StatusText: Service unavailable (with message) ResponseText: Exception: Invalid field name given: field_template2_popup_fields is not a Field Collection field. in FieldCollectionItemEntity->__construct() (line 123 of /vagrant/web/local.example.com/src/drupal/drupal/sites/all/modules/field_collection/field_collection.module).Uncaught exception thrown in session handler.PDOException: SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'uid' cannot be null: INSERT INTO {sessions} (sid, ssid, uid, cache, hostname, session, 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] => 1ZVP1zkGqyAoiEf4CZ3m5wCOwYl-INGbEcjT_nVj7u8 [:db_insert_placeholder_1] => [:db_insert_placeholder_2] => [:db_insert_placeholder_3] => 0 [:db_insert_placeholder_4] => 192.168.33.254 [:db_insert_placeholder_5] => batches|a:15:{i:100;b:1;i:101;b:1;i:102;b:1;i:103;b:1;i:104;b:1;i:105;b:1;i:106;b:1;i:107;b:1;i:108;b:1;i:109;b:1;i:110;b:1;i:111;b:1;i:112;b:1;i:113;b:1;i:114;b:1;}messages|a:2:{s:7:"warning";a:2:{i:0;s:223:"There are paths in the system that are still not configured for Site Catalyst! Please <a href="http://dev.example.com/admin/config/development/example-site-catalyst/pending">review and configure</a> these pages immediately.";i:1;s:237:"The Date API requires that you set up the <a href="/?q=admin/config/regional/settings">site timezone and first day of week settings</a> and the <a href="/?q=admin/config/regional/date-time">date format settings</a> to function correctly.";}s:6:"status";a:1:{i:0;s:127:"Meta tags (quick) installed. To start, please visit <a href="/?q=admin/config/search/metatags_quick">module settings screen</a>";}} [:db_insert_placeholder_6] => 1356035867 ) in _drupal_session_write() (line 209 of /vagrant/web/local.example.com/src/drupal/drupal/includes/session.inc).