Problem with printing output using PHP library

Question

I am using the PHP library tools on a we hosting service( with cURL enabled). I have so far tried 2 tools but I cant get the output of my code to print to the screen.

http://github.com/jdp/twitterlibphp - PHP library

Sample code -

<?php
require("twitter.lib.php");

$twitter = new Twitter("xxxx", "xxxxx");
$public_timeline = $twitter->getPublicTimeline();

echo'<pre>';
print_r( $public_timeline );
echo'</pre>';

?>

I don't get any output. What can be the problem? Do I need to install any modules or packages? Please Help