Nav links not working

<?php function my_content_nav( $nav_id ) {
	global $wp_query;?>
	<nav id="<?php	echo $nav_id;?>">
		<?php if ( $wp_query->max_num_pages > 1 ) :?>
		<h3 class="assistive-text"><?php _e('Post navigation', 'my');?></h3>
		<?php next_posts_link(__('<span class="meta-nav nav-previous">&larr; Older posts</span>', 'my'));?>
		<?php previous_posts_link(__('<span class="meta-nav nav-next">Newer posts &rarr;</span>', 'my'));?>
		<div class="clear"></div>
		<?php endif; ?>
	</nav><!-- #nav-above -->
<?php } ?>

<?php function my_post_nav( $nav_id ) {
	global $wp_query; ?>
	<?php if ( $wp_query->max_num_pages > 1 ) :?>
	<nav id="<?php	echo $nav_id;?>">
		<h3 class="assistive-text"><?php _e('Post navigation', 'my');?></h3>
		<?php previous_post_link( '%link', '<span class="meta-nav">&larr;</span> %title' )?>
		<?php next_post_link( '%link', '%title <span class="meta-nav">&rarr;</span>' )?>
		<div class="clear"></div>
	</nav><!-- #nav-above -->
<?php } ?>

Please let me know what is wrong with the above code it is breaking my wordpress install.