Maybe too late answer, but can help someone.
Pagination is part in template where we got links to navigate to previous/next page. For example, in TwentyTen theme for Main Index (index.php) we have this part of code:
get_template_part( 'loop', 'index' );
?>
</div><!-- #content -->
</div><!-- #container -->
Now, we put <?php do_action("ppc"); ?> right before </div><!-- #content --> to enable Posts per Cat, and got something like this:
get_template_part( 'loop', 'index' );
?>
<?php do_action("ppc"); ?>
</div><!-- #content -->
</div><!-- #container -->