Smarty is supported only in PHP 4.0.6 or later.

Smarty versions previous to 2.0 require the PEAR libraries. Be sure to include
the path to the PEAR libraries in your php include_path. Config_file.class.php
uses the PEAR library for its error handling routines. PEAR comes with the PHP
distribution. Unix users check /usr/local/lib/php, windows users check
C:/php/pear.