error when used wp-pagenavi

<?php
                    if(is_home()){

                        query_posts('cat=-8,-9'); <!--not show cat products and news-->
                    }

                  ?>
                    <?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
                    <div class="newpost_item">
                        <h1><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h1>
                        <p class="metadata_post"> Post By : <?php the_author(); ?></p>
                        <?php
                            if(has_post_thumbnail()){
                            the_post_thumbnail();
                            }
                        ?>                       

                        <p>
                            <?php the_content(''); ?>
                        </p>
                        <p class="read_more"><a href="<?php the_permalink(); ?>">Chi tiết</a></p>
                    </div><!--End DIV #newpost_item -->
                    <?php Endwhile; ?>
                    <?php else: ?>

error : only page 1 , when i go to page 2, the address was moved page/2 but the content does not change.
my site : http://nhikhucvn.com
help me ! thanks

http://wordpress.org/extend/plugins/wp-pagenavi/