Smarty must be configured properly. Smarty is included in PEAR distributions, or below PEAR.

If you install Smarty, you must ensure that Smarty dir is included in PATH.

You can add Smarty inside lib subdirectory, in this case you must change

require('Smarty/Smarty.class.php');

for

require('lib/Smarty.class.php');

If your system is configured with save PHP, I recommend to put Smarty in lib directory.