default value of $total_rows in Pagination class should be number. And fix User Guide Pagination Class's Example which uses string to number variable.
diff --git a/user_guide/libraries/pagination.html b/user_guide/libraries/pagination.html
index e86ec13..3c366a6 100644
--- a/user_guide/libraries/pagination.html
+++ b/user_guide/libraries/pagination.html
@@ -71,8 +71,8 @@
<code>
$this->load->library('pagination');<br /><br />
$config['base_url'] = 'http://example.com/index.php/test/page/';<br />
-$config['total_rows'] = '200';<br />
-$config['per_page'] = '20';
+$config['total_rows'] = 200;<br />
+$config['per_page'] = 20;
<br /><br />
$this->pagination->initialize($config);