If you still haven’t found a solution, I wrote a post about how to set up wp-pagenavi with platform free edition. But it is in french, so here are the main steps:
Be sure you have wp-pagenavi installed and turned on.
Use a FTP client to edit this file of your wordpress installation: wp-content/themes/platform/sections/wp/section.pagination.php
Look for the following lines:
function section_template() { ?>
<?php if(function_exists('wp_pagenavi') && show_posts_nav() && VPRO):?>
<?php wp_pagenavi(); ?>
<?php elseif (show_posts_nav()) : ?>
<div class="page-nav-default fix">
<span class="previous-entries"><?php next_posts_link(__('← Previous Entries','pagelines')) ?></span>
<span class="next-entries"><?php previous_posts_link(__('Next Entries →','pagelines')) ?></span>
</div><!-- page nav -->
<?php endif;?>
<?php }
and replace the first line by this one:
<?php if(function_exists('wp_pagenavi') && show_posts_nav()):?>
Hope it helps ??