wp pagenavi

hi,
i have a problem with wp pagenavi when i set the permalinks to postname it returns to page not found i have to show pagination in portfolio i am using wordpress fluxux theme i have write paginatio code in template-portfolio-grid.php
here is my code
<?php
$paged = (get_query_var(‘paged’)) ? get_query_var(‘paged’) : 1;
$loop = new WP_Query( array( ‘post_type’ => ‘portfolio’, ‘paged’=>$paged ) );?>
<?php
if ( function_exists( ‘wp_pagenavi’ ) ) {
wp_pagenavi( array( ‘query’ => $loop ) );
wp_reset_postdata();
}
?>

i want to show pagination at the top of my portfolio
any help??
thanks in advance