Hi, I'm getting an error in my error log:

[15-Nov-2012 08:46:20 UTC] PHP Warning: require() [<a href='function.require'>function.require</a>]: Filename cannot be empty in /ZencartDirectory/includes/templates/template_default/templates/tpl_page_not_found_default.php on line 23
[15-Nov-2012 08:46:20 UTC] PHP Fatal error: require() [<a href='function.require'>function.require</a>]: Failed opening required '' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /ZencartDirectory/includes/templates/template_default/templates/tpl_page_not_found_default.php on line 23

No changes have been made to this file (tpl_page_not_found_default.php) - I have also not customized this file (I have no equivalent file in my personalized template directory). Is having a tpl_page_not_found_default equivalent in my custom template folder required?