[_ck_]

If this appears in your front-page.php, then you have bbPress 1.0.x and you have a bug

<?php bb_latest_topics_pages( array( 'before' => '<div class="nav">', 'after' => '</div>' ) ); ?>

The same bug was in some rare cases of 0.9

and I programmed around it in topics-per-page

I doubt it will work properly on 1.0 but you can try installing the plugin, remove the above line and replace it with

<div class="nav"><?php front_page_pages(); ?></div>