wordpress portfolio page not found

[brainfo]

hi. I successfully created a portfolio section in wordpress with quicksand with the help of http://wp.tutsplus.com/tutorials/theme-development/create-a-quicksand-portfolio-with-wordpress/
site. And now am having problem that when ever i click any view detail page it shows
"
This is somewhat embarrassing, isn’t it?

It seems we can’t find what you’re looking for. Perhaps searching, or one of the links below, can help "

my function.php code related to portfolio

// Registering Menus
    function register_menu() { register_nav_menu('navigation', __('Main Navigation')); }
    add_action('init', 'register_menu');

    // Register our Scripts
    function register_js() {
        if (!is_admin()) {
            wp_deregister_script('jquery');
            wp_register_script('jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js');
            wp_register_script('quicksand', get_template_directory_uri() . '/js/jquery.quicksand.js', 'jquery');
            wp_register_script('easing', get_template_directory_uri() . '/js/jquery.easing.1.3.js', 'jquery');
            wp_register_script('custom', get_template_directory_uri() . '/js/jquery.custom.js', 'jquery', '1.0', TRUE);
            wp_register_script('prettyPhoto', get_template_directory_uri() . '/js/jquery.prettyPhoto.js', 'jquery');


            wp_enqueue_script('jquery');
            wp_enqueue_script('quicksand');
            wp_enqueue_script('prettyPhoto');
            wp_enqueue_script('easing');
            wp_enqueue_script('custom');
        }
    }

    add_action('init', 'register_js');

    // Register our Styles
    function register_styles()
    {
        if (!is_admin()) {
            wp_register_style('prettyPhoto', get_template_directory_uri() . '/css/prettyPhoto.css');
            wp_enqueue_style( 'prettyPhoto');
        }       
    }

    add_action('init', 'register_styles');

    //Setting Up Feature Images
    if ( function_exists( 'add_theme_support' ) ) {
        add_theme_support( 'post-thumbnails' );
        set_post_thumbnail_size( 56, 56, true );
        add_image_size( 'portfolio', 295, 150, true ); 
    }

add_theme_support( 'post-thumbnails' );
    // Include the portfolio functionality
    include("portfolio/portfolio-post-type.php");

and portfolio-post-type.php which is inside portfolio folder
`

    <?php  

        // function: post_type BEGIN  
        function post_type()  
        {  
                    $labels = array(  
    'name' => __( 'Portfolio'),   
    'singular_name' => __('Portfolio'),  
    'rewrite' => array(  
        'slug' => __( 'portfolio' )   
    ),  
    'add_new' => _x('Add Item', 'portfolio'),   
    'edit_item' => __('Edit Portfolio Item'),  
    'new_item' => __('New Portfolio Item'),   
    'view_item' => __('View Portfolio'),  
    'search_items' => __('Search Portfolio'),   
    'not_found' =>  __('No Portfolio Items Found'),  
    'not_found_in_trash' => __('No Portfolio Items Found In Trash'),  
    'parent_item_colon' => ''  
);  
           $args = array(  
    'labels' => $labels,  
    'public' => true,  
    'publicly_queryable' => true,  
    'show_ui' => true,  
    'query_var' => true,  
    'rewrite' => true,  
    'capability_type' => 'post',  
    'hierarchical' => false,  
    'menu_position' => null,  
    'supports' => array(  
        'title',  
        'editor',  
        'thumbnail'  
    )  
);   


    register_post_type(__( 'portfolio' ), $args);          
            // We will fill this function in the next step   
        } // function: post_type END  


      // function: portfolio_messages BEGIN  
    function portfolio_messages($messages)  
    {  
        $messages[__( 'portfolio' )] =   
            array(  
                0 => '',   
                1 => sprintf(('Portfolio Updated. <a href="%s">View portfolio</a>'), esc_url(get_permalink($post_ID))),  
                2 => __('Custom Field Updated.'),  
                3 => __('Custom Field Deleted.'),  
                4 => __('Portfolio Updated.'),  
                5 => isset($_GET['revision']) ? sprintf( __('Portfolio Restored To Revision From %s'), wp_post_revision_title((int)$_GET['revision'], false)) : false,  
                6 => sprintf(__('Portfolio Published. <a href="%s">View Portfolio</a>'), esc_url(get_permalink($post_ID))),  
                7 => __('Portfolio Saved.'),  
                8 => sprintf(__('Portfolio Submitted. <a target="_blank" href="%s">Preview Portfolio</a>'), esc_url( add_query_arg('preview', 'true', get_permalink($post_ID)))),  
                9 => sprintf(__('Portfolio Scheduled For: <strong>%1$s</strong>. <a target="_blank" href="%2$s">Preview Portfolio</a>'), date_i18n( __( 'M j, Y @ G:i' ), strtotime($post->post_date)), esc_url(get_permalink($post_ID))),  
                10 => sprintf(__('Portfolio Draft Updated. <a target="_blank" href="%s">Preview Portfolio</a>'), esc_url( add_query_arg('preview', 'true', get_permalink($post_ID)))),  
            );  
        return $messages;  

    } // function: portfolio_messages END  

        // function: portfolio_filter BEGIN  
    function portfolio_filter()  
    {  
        register_taxonomy(  
            __( "filter" ),  
            array(__( "portfolio" )),  
            array(  
                "hierarchical" => true,  
                "label" => __( "Filter" ),  
                "singular_label" => __( "Filter" ),  
                "rewrite" => array(  
                    'slug' => 'filter',  
                    'hierarchical' => true  
                )  
            )  
        );  
    } // function: portfolio_filter END  


add_action( 'init', 'post_type' );  
add_action( 'init', 'portfolio_filter', 0 );  
add_filter( 'post_updated_messages', 'portfolio_messages' ); 

`
Any help will be greatly appreciated. Thanks in advance.

[blocblue]

You've added a custom re-write slug, but have you flushed the rewrite rules?
http://codex.wordpress.org/Function_Reference/register_post_type#Flushing_Rewrite_on_Activation

You can do this programmatically, as per the link above, or by updating the permalink structure via the admin panel (note you don't need to change anything, just resave).