custom tag cloud and pagination problem

My project uses Simple Tags plugin to generate a tag cloud for frontend with urls like ‘mysite.com/tag/<tag-name>’. I have a custom object type called ‘tours’ in the project. On clicking a particular tag cloud link , i want tours tagged with that particular tag to be displayed and paginated using wp_pagenavi plugin. Right now, i am only able to see the first page of tours filtered by tags. On going to page 2 i get a 404 error. The tours for a tag are displayed using a file called tag.php in the root of my custom theme folder.

I know very little about taxonomies .I want to know if the ‘post_tag’ taxonomy is relevant here. Please help me solve this problem. The site is https://abgtours.ru . Any help will be appreciated.

The code of tag.php is

<?php
/**
 * The template used to display Tag Archive pages
 *
 * @package WordPress
 * @subpackage Twenty_Eleven
 * @since Twenty Eleven 1.0

Template Name: Tag Page*/
get_header(); ?>
<?php //print_r($_REQUEST); echo single_tag_title('',false);
$url=urldecode($_SERVER['REQUEST_URI']);
//$matches=array();
$url_array=explode('/', $url);

$idx=0;
$v1=0;

foreach($url_array as $w)
{
	if($w==='tag')
	{
		break;
	}
	$idx++;
}

foreach($url_array as $w)
{
	if($w==='page')
	{
		break;
	}
	$v1++;
}

//echo "<b>".$url_array[$idx+1]."</b>";

$term=$url_array[$idx+1];

$page=$url_array[$v1+1];

//$mp = query_posts("taxonomy=post_tag&post_type=tours&post_tag='".$term."'&order=DESC&showposts=10");
//$mp = query_posts("taxonomy=post_tag&post_type=tours&order=DESC&showposts=10");

$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
$args=array(
   'post_type'=>'tours',
   'taxonomy' => 'post_tag',
   'post_tag'=>$term,
   'posts_per_page' =>10,
   'paged'=>$paged
);
$temp = $wp_query;
$wp_query= null;
$wp_query = new WP_Query($args);

//die;
?>

<div class="content">
  <div class="main">
    <div class="leftpart">
    <div class="navigation">
   <?php if(function_exists('bcn_display'))
    {
        bcn_display();
    }?>

      </div>
      <div class="tourslist">
      	<div>

        <ul>
        <li class="tourslist_li" style="list-style:none">
            <div class="tourheadding" style="background:none">
              <div class="headdingleft">
                <h3>
                  <?php echo "Архив Тегов: ". $term; ?>
                   </h3>
               </div>
              <div class="tourprice helvetica-neue-light">
                &nbsp;
              </div>
            </div>
            </li>
          </ul>

        </div>
        <?php if ( $wp_query->have_posts() ) : ?>
        <ul>
          <?php
		 while ( $wp_query->have_posts() ) :  $wp_query->the_post(); 

		 //global $post;
		 //$pst_id = $post->ID;

		 ?>
          <?php $meta = get_post_meta($post->ID, 'abg_tours_download_brochure', true); ?>
          <?php $tourimg = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ) ,'list-thumb'); ?>
          <li class="tourslist_li" style="list-style:none">
            <div class="tourheadding">
              <div class="headdingleft">
                <h3><a href="<?php the_permalink(); ?>">
                  <?php the_title();  ?>
                  </a> </h3>
                <p><?php echo get_post_meta($post->ID,'abg_tours_days_nights',true); ?></p>
              </div>
              <div class="tourprice helvetica-neue-light">
                <?php if(get_post_meta($post->ID,'abg_tours_price',true)) { ?>
                <img src="<?php bloginfo('template_url'); ?>/images/from_ru.png" /> $<?php echo get_post_meta($post->ID,'abg_tours_price',true);?>
                <?php } ?>
              </div>
            </div>
            <div class="toursdetail">
               <?php if($tourimg[0]) {?><div class="placeimage"><a href="<?php the_permalink(); ?>"> <span class="newimg"></span>
                <img src="<?php echo $tourimg[0]; ?>" width="241" height="139" alt="" /> </a> </div><?php } ?>
              <div class="<?php if($tourimg[0]) {?>toursright<?php }else{ ?>toursright2<?php } ?>">
                <div class="citylist">
                  <p><strong>Тип Тура:</strong></p>
                  <p>
                    <?php $terms = get_the_terms($post->ID, 'tourstype');
				  		$types = '';
					  foreach($terms as $tourtype ){
						  if($tourtype->taxonomy == 'tourstype' ){
							 $types[] = $tourtype->name;
						  }
					  }

					 echo implode(", ",$types);

				     ?>
                  </p>
                </div>
                <div class="citylist">
                  <p><strong>Города:</strong></p>
                  <p>
                    <?php $terms1 = get_the_terms($post->ID, 'tourscat');
				  $cities = '';
				  foreach($terms1 as $tourcity ){
					 $cities[] = $tourcity->name;
  				  }
					 echo implode(", ",$cities);
				     ?>
                  </p>
                </div>
                <div class="description">
                  <h5>Описание:</h5>
                  <p><?php echo substr(get_the_content(),0,145); ?></p>
                </div>
                <div class="tourshare"> <span class='st_email_large' st_title='<?php the_title(); ?>' st_url='<?php the_permalink(); ?>' displayText='Отправить имайл' style="float:left; padding-top:6px !important;">Отправить имайл</span> <span class="float-left" style="padding-top:5px !important;">|</span> <span class='st_sharethis' st_title='<?php the_title(); ?>' st_url='<?php the_permalink(); ?>' style="padding-left:-10px;" displayText='Поделиться'></span> <span class="float-left" style="padding-top:5px !important;">|</span> <a href="<?php the_permalink(); ?>" class="moredetail">Детали Тура</a> </div>
              </div>
            </div>
          </li>
          <!-- #post-<?php the_ID(); ?> -->

          <?php endwhile; // end of the loop. ?>
        </ul>
        <?php else : ?>
        <ul>
          <li class="tourslist_li" style="list-style:none; min-height:200px;">
            <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 -->
          </li>
        </ul>
        <?php endif;

 ?>
      </div>
      <div class="pagi" style="position:relative">
        <?php  //kriesi_pagination(); ?>
        <?php wp_pagenavi(array( 'query' => $wp_query ));
		$wp_query = null;
$wp_query = $temp;
wp_reset_query();
		?>
      </div>
    </div>
    <?php get_sidebar(); ?>
  </div>
</div>

<?php get_footer(); ?>