In header.php;

<h1 id=”fittext”><a href=”<?php echo home_url(); ?>/”><?php bloginfo(‘name’); ?></a><i><?php /* bloginfo(‘description’)*/;?></i></h1>

wrapping the above by <li> & </li> will remove the validation error but does not seem to affect IE8 ill performance.

Moreover this may mess up the display of header!!!

You have to disregard the css3 validation error if you want to take care of IE8.