Syntax Error in Conditional Custom Field Code

Hi everyone,

I’m trying to have a bit of custom text (from a custom field) display, and if a page doesn’t have that custom field, than have a default/standby bit of text appear. Here is the code I’m using, and I’m receiving a “unexpected T_ENDIF” syntax error. I’m a true beginner in PHP, so if it’s something obviously wrong (which I’m sure it is), please be kind 🙂

<?php if (have_posts()) : while (have_posts()) : the_post(); ?>
    <?php $pageHeader=get_post_meta($post->ID, 'pageHeader', true); ?>
    <?php if ( $pageHeader ) { ?>

    <!-- with custom page header -->
	<?php echo $pageHeader; ?>
    <?php } else { ?>

    <!-- without custom page header -->
	Sample code
    <?php endif; ?>

      <?php
			if ( has_post_thumbnail() ) {
			the_post_thumbnail();
			}
			?> 

			<h1><?php the_title(); ?></h1>
			<?php the_content(); ?>

		<?php endwhile; endif; ?>

Any ideas? Any help is greatly appreciated.