Warning: require_once(PEAR.php) [function.require-once]: failed to open stream: No such file or directory in /var/www/html/webmail.template/htdocs/lib/Registry.php on line 4

Fatal error: require_once() [function.require]: Failed opening required 'PEAR.php' (include_path='.:/usr/share/pear:/usr/share/php') in /var/www/html/webmail.template/htdocs/lib/Registry.php on line 4