Fatal error

Please use the drush version, as it's more likely to work any time. We'll probably drop the direct link out of there.

this is an error in logging and alerts (the value is not used at all in the remainder of the function, if you remove the function, the next issue is that the theme() function is unknown.

This happens when logging&alert watchdog is called very early in the bootstrap process. I did this to solve it:

  if (variable_get('errorlog_' . $log['severity'], FALSE)) {
    // Remove this:
    // $language = user_preferred_language($log['user']);

    // Make sure that $log['variables'] is always an array to avoid
    // errors like in issue http://drupal.org/node/1325938
    if (!is_array($log['variables'])) {
      $log['variables'] = array();
    }

    // Send themed alert to the web server's log. But only if the theme function exists
    if (function_exists('theme')) {
      $message = theme('errorlog_format', $log);
    }
    else {
      $message = print_r($log);
    }
    error_log($message);
  }

Thanks Reinier. Please roll that into a patch.

Fixed in both 7.x-2.x and 6.x-2.x branches, just pushed to d.o.