nazakatali32 on ""do_shortcode " Not working."

Hi, This is code

<?php echo do_shortcode("[tab:Tab1]") ?>
//HTML contents
<?php echo do_shortcode('[tab:END]') ?>

It is not working properly. It only prints the Values
as
[tab:Tab1]
//HTML contents
[tab:END]
But not becomes tabs .
This is plugin site:
http://wordpress.org/plugins/posttabs/