Navigation buttons always return me to the first page

nothing to do with wp-pagenavi;

the query should also contain the ‘paged’ parameter;
http://codex.wordpress.org/Class_Reference/WP_Query#Pagination_Parameters

for example, try:

query_posts('cat=66&paged='.get_query_var('paged'));

or alternatively try to merge your cat=66 into the existing query:

global $wp_query; $args = array_merge( $wp_query->query_vars, array( 'cat' => 66 ) ); query_posts( $args );

http://codex.wordpress.org/Function_Reference/query_posts#Preserving_Existing_Query_Parameters

Hello @alchymyth
I am also having the same problem on my home page…
I see your response for solution but dont know exactly how to implement.
Can you please clarify a little more…

here is my code for Index.php, and I am using Zenshop theme with cart66 lite on wp-pagenavi version 2.83

Here is the code for index.php:

<?php get_header(); ?>

<?php

if(get_option('zens_home') == "blog") { ?>	

<?php include (TEMPLATEPATH . '/lib/blog-home.php'); ?>

<?php } else { ?>

<div id="featured">

<div class="flexslider">

	<ul class="slides">

	<?php 

		$slide = get_option('zens_slide_cat');

		$count = get_option('zens_slide_count');

		$slide_query = new WP_Query( 'post_type=products&product-category='.$slide.'&posts_per_page='.$count.'' );

		while ( $slide_query->have_posts() ) : $slide_query->the_post();

	?>	

<li>
		<a>"><img class="slideimg" src="<?php bloginfo('stylesheet_directory'); ?>/timthumb.php?src=<?php echo get_image_url()?>&h=300&w=500&zc=2" title="" alt="" /></a>

		<div class="flex-caption">

			<h2><a>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><?php the_title(); ?></a></h2>

			<?php wpe_excerpt('wpe_excerptlength_slide', ''); ?>

			<div class="slidetab">

			<span class="sprice"><?php $price=get_post_meta($post->ID, 'w2f_price', true); echo $price; ?></span>

			<span class="spdetails"><a>">Product Details</a></span>

			</div>

		</div>

</li>
	<?php endwhile; ?>

</div>

</div>

<div id="home-content" class="clearfix">

<ul id="shelf">

	<?php

		$home_count = get_option('zens_home_count');

		$temp = $wp_query;

		$wp_query= null;

		$wp_query = new WP_Query();

		$wp_query->query('posts_per_page='.$home_count.'&post_type=products'.'&paged='.$paged);

	?>

	<?php while ($wp_query->have_posts()) : $wp_query->the_post(); ?>	

	<li class="box" id="post-<?php the_ID(); ?>">

	<?php $disc = get_post_meta($post->ID, 'w2f_discount', true); ?>

	<?php if ( $disc ) { ?>

			<span class="salebadge"></span>

	<?php }?>

		<div class="boxtitle">

			<h2><a>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><?php the_title(); ?></a></h2>

		</div>

		<a>"><img class="productshot" src="<?php bloginfo('stylesheet_directory'); ?>/timthumb.php?src=<?php get_image_url(); ?>&h=200&w=170&zc=2" alt=""/></a>

		<div class="pricetab clearfix">

		<?php if ( $disc ) { ?>

			<span class="oldprice"><del> <?php echo get_post_meta($post->ID, 'w2f_disc-price', true) ?> </del></span>

		<?php }?>

		<span class="price"><?php $price=get_post_meta($post->ID, 'w2f_price', true); echo $price; ?></span>

		<span class="prodetail"><a>">Details</a></span>

		</div>

	<?php endwhile; ?>

	<div class="clear"></div>

	<?php getpagenavi(); ?>

	<?php $wp_query = null; $wp_query = $temp;?>

</div>

<?php get_footer(); ?>

<?php } ?>

[Please post code or markup between backticks or use the code button. Or better still – use a pastebin. Your posted code has now been permanently damaged/corrupted by the forum’s parser.]

thanks in advance for any help.
And here is the link:
http://bhimphedi.com/pearl