Wordpess Custom Query and pagination attempt

<?php
/**
 * The template for displaying Category Archive pages.
 *
 * @package WordPress
 * @subpackage Twenty_Eleven
 * @since Twenty Eleven 1.0
 */

get_header(); ?>

        <section id="primary">
            <div id="cat-content" role="main">

<?php
// Create a new filtering function that will add our where clause to the query
// Retrieve consistent random set of posts with pagination
function mam_posts_query($query) {
    global $mam_posts_query;
    if ($mam_posts_query && strpos($query, 'ORDER BY RAND()') !== false) {
       $query = str_replace('ORDER BY RAND()',$mam_posts_query,$query);
    }
    return $query;
}
add_filter('query','mam_posts_query');

function filter_where( $where = '' ) {
    // posts in the last 120 days
    $where .= " AND post_date > '" . date('Y-m-d', strtotime('-120 days')) . "'";
    return $where;
}

$seed = date('Ymdh');
global $mam_posts_query;

add_filter( 'posts_where', 'filter_where' );
$mam_posts_query = " ORDER BY rand($seed) "; // Turn on filter

$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;

$totalpostcount = count(query_posts(array('posts_per_page'=>-1,'cat'=>6) ) );
$offset = ($paged-1) * 9;
query_posts( array('paged'=> $paged ,'posts_per_page'=>9,'cat'=>6,'orderby'=>'rand','offset' => $offset, ) );
$wp_query->found_posts=$totalpostcount;
$wp_query->max_num_pages = ceil($totalpostcount / 9);

$mam_posts_query = ''; // Turn off filter
remove_filter( 'posts_where', 'filter_where' );

$counter=1;
if ( have_posts() ) :
   while ( have_posts() ) : the_post();
      if($counter==1||$counter==4||$counter==8) echo '<ul class="cat-col-' . $counter . '">';

        if($counter==1||$counter==9) echo '<li class=type-3>';
        if($counter==2||$counter==3||$counter==4||$counter==5) echo '<li class=type-1>';
        if($counter==6||$counter==7||$counter==8) echo '<li class=type-2>';

        echo '<a href="' . get_permalink( ) . '"><span class="lower"></span><span class="upper"><strong>' . get_the_title() . '</strong><em>View image »</em></span>';
        if($counter==1||$counter==9) the_post_thumbnail('cat-large-square', array('class' => 'cat-large-square'));
        if($counter==2||$counter==3||$counter==4||$counter==5) the_post_thumbnail('cat-small-square', array('class' => 'cat-small-square'));
        if($counter==6||$counter==7||$counter==8) the_post_thumbnail('cat-rect', array('class' => 'cat-rect'));



      echo '</a></li>';
      if($counter==3||$counter==7||$counter==9) echo '</ul>';
      $counter++;
   endwhile;?>
<div class="nav-previous"><?php previous_posts_link( __( '<span class="meta-nav">&larr;</span>Go Back', 'twentyeleven' ) ); ?>
</div>
                                    <div class="nav-next"><?php next_posts_link( __( 'More in this Gallery<span class="meta-nav">&rarr;</span>', 'twentyeleven' ) ); ?></div>


                <?php /* twentyeleven_content_nav( 'nav-below' ); */ ?>

            <?php else : ?>

                <article id="post-0" class="post no-results not-found">
                    <header class="entry-header">
                        <h1 class="entry-title"><?php _e( 'Nothing Found', 'twentyeleven' ); ?></h1>
                    </header><!-- .entry-header -->

                    <div class="entry-content">
                        <p><?php _e( 'Apologies, but no results were found for the requested archive. Perhaps searching will help find a related post.', 'twentyeleven' ); ?></p>
                        <?php get_search_form(); ?>
                    </div><!-- .entry-content -->
                </article><!-- #post-0 -->

            <?php endif; ?>

            </div><!-- #content -->
        </section><!-- #primary -->

<?php get_footer(); ?>