Open your file header.php (appearance—>editor–>Header.php) and put this lines :
[ Moderator note: please wrap code in backticks or use the code button. ]
<?php do_action( 'bp_before_main_nav' ); ?>
<!-- NAVIGATION START -->
<nav class="main-nav iegradient" id="main-navigation" role="navigation">
<div class="innerwrap">
<?php if( has_nav_menu('primary') ):
wp_nav_menu( array( 'theme_location' => 'primary', 'container' => false, 'menu_class' => 'sf-menu', 'fallback_cb' => '','walker' => new Custom_Description_Walker ));
else:
echo '<ul class="sf-menu">';
echo wp_list_categories('orderby=name&show_count=0&title_li=');
echo '';
endif;
?>
</div>
</nav>
<!-- NAVIGATION END -->
<?php do_action( 'bp_after_main_nav' ); ?>
Before this line :
<!-- HEADER START -->
Then delete this same lines after :
<!-- HEADER END -->
<?php do_action( 'bp_after_header' ); ?>
Make you had make a backup of your theme before do this !!!