Using automated queries from a script to calculate a google pagerank breaks google's terms of service, thus they're known to ban servers for it. You can test that this is what's happening to you:

1) Open classes/pagerank.php and change

$result[0]=$contents;

to

$result[0]=$contents;
echo "<p>Google reports: ". $result[0] ."</p>";

2) Create this little test file (name it test.php if you like) in your main WSN Knowledge Base directory and visit it in your web browser:

<?php require 'classes/pagerank.php';
$pr = new GooglePR();
$url = 'http://www.yahoo.com';
$rank = $pr->GetPR($url);
echo "the pagerank is ". $rank; ?>

You'll probably see a message from google:


You can appeal to google if you wish. If you've regenerated pageranks before, be sure not to do that again (let the system update them more slowly to avoid angering google).