Warning: require(includes/application_top.php): failed to open stream. No such file..

Just upgraded the security patch and now getting the following when trying to access the new admin page.

Warning: require(includes/application_top.php) [function.require]: failed to open stream: No such file or directory in /home/myname/public_html/admin/index.php on line 23

Warning: require(includes/application_top.php) [function.require]: failed to open stream: No such file or directory in /home/myname/public_html/admin/index.php on line 23

Fatal error: require() [function.require]: Failed opening required 'includes/application_top.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/myname/public_html/admin/index.php on line 23

Any ideas