EllisLab/CodeIgniter — pull request #1968 by CoeusCC (2012-11-05 12:38:48+00:00)
Title: Correction for variables in db_active_rec.php (line 1407); causes update_batch() to fail

Using update_batch() with an associative array fails and throws and error at live 1407 of db_active_rec.php.

Amir Syafrudin proposed the fix here - http://stackoverflow.com/questions/11279262/update-database-field-error-codeigniter (answer 2, as of this pull request)