I keep getting this:

Warning: main(wp-includes/class-smarty.php): failed to open stream: No such file or directory in /home/fallen/public_html/wpmu/wp-inst/wpmu-settings.php on line 27

Fatal error: main(): Failed opening required ‘wp-includes/class-smarty.php’ (include_path=”) in /home/fallen/public_html/wpmu/wp-inst/wpmu-settings.php on line 27