EllisLab/CodeIgniter — pull request #1969 by CoeusCC (2012-11-05 13:25:31+00:00)
Title: Error on line 1407 of db_active_rec.php traces to mis-named variables

Corrected variables to $k2 and $v2

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)