PEAR's Net_Whois CLass doubt

Hi guys,

i have downloaded the whois.php file but how can i actually use it ?

i uploaded the PEAR.php file and Whois.php file into same folder..

my code (according to a reference book):
require 'Whois.php';
$server = 'whois.networksolutions.com';
$query = 'example.org';
$data = Net_Whois::query($server, $query);

it suppose to show some results... but not it shows a fatal error occured.

the error :
Fatal error: Call to a member function on a non-object in /home/eonenet/public_html/whois/Whois.php on line 131


Do i actually need to amend the Whois.php file that i downloaded ?? what actually makes such error occured.

p,s: downloaded from http://pear.php.net/package-info.php?package=Net_Whois

PLease advise.