PHP Fatal error: Call to undefined function webform_menu_to_arg()


I got the latest pressa release which has security update of drupal 7.38. I created an empty database in mysql and ran the DB scripts that came with the pressa release to populate the database. I unzip the full install under the sites folder and update the settings.php with the db information but when I go to the site in browser, it displays nothing. In the htttpd log, I see the error

[Tue Aug 11 21:19:16 2015] [error] [<client IP>] PHP Fatal error:  Call to undefined function webform_menu_to_arg() in /var/www/html/includes/ on line 816

The php running on my machine is :-

PHP 5.5.22 (cli) (built: Feb 20 2015 02:02:59)
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2015 Zend Technologies
    with Zend OPcache v7.0.4-dev, Copyright (c) 1999-2015, by Zend Technologies



You should do updating after install full demo. Also, pressa version 1.2 is ready Drupal 7.38. So, please download latest version and install without upgrade step.

Thank you.