Error en el archivo index.php

Hola!
Hoy he encontrado un theme que me ha gustado mucho por internet, pero al instalarlo me ha dado error en el archivo index.php, concretamente este error:
Parse error: syntax error, unexpected 'endwhile' (T_ENDWHILE) in \wp-content\themes\Basico\index.php on line 61

Aquí dejo mi index.php:

<?php
global $options;
foreach ($options as $value) {
if (get_settings( $value['id'] ) === FALSE) { $$value['id'] = $value['std']; } else { $$value['id'] = get_settings( $value['id'] ); }
}
?>
<?php get_header(); ?>
<div id="slider">
<img src="<?php bloginfo('template_url');?>/images/slider/1.jpg" alt="" />
<img src="<?php bloginfo('template_url');?>/images/slider/2.jpg" alt="" />
<img src="<?php bloginfo('template_url');?>/images/slider/3.png" alt="" />
</div>
<div id="wrap">
	<div id="main">
		    	<?php if (have_posts()) : ?>
    	<?php while (have_posts()) : the_post();
		$thumbnail = wp_get_attachment_image_src(get_post_thumbnail_id(), 'large');
		?>
        	<div class="poster">
            	<div class="leftside">
            		<div class="inline-byline">
            			<a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>" class="date-num"><?php the_time('j') ?></a>
            			<a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>" class="date-month"><?php the_time('M') ?></a>
            			<span>Autor:</span> <span class="inline-byline-author"><?php the_author_posts_link(); ?></span>
            			<span class="comment"><?php comments_popup_link('0', '1', '%'); ?></span>
                     </div>
            	</div>

			<div class="post postcontent">
			<?
			// checks if thumbnails are disabled
			if ($xs_disable_thumbnails_archieve == "true") { ?>
		  <? } else { ?>
            	<?php
					if ( has_post_thumbnail() ) {
					// the current post has a thumbnail
					?>
                    <div class="thumbnail-wrap">
						<a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><img src="<?php echo $thumbnail[0]; ?>" height="270" width="560" alt="<?php the_title(); ?>" class="thumbnail" /></a>
                    </div><!-- /thumbnail-wrap -->
					<? } else {
					// the current post lacks a thumbnail
					?>
				<? } ?>
			<? } ?>
            <h2 class="entry-title"><a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></h2>
            <?
			// checks if the byline is disabled
			if ($xs_disable_inline_byline == "true") { ?>
			<?
			// if not show byline
	 		} else { ?>

            <? } ?>
		<?php the_excerpt(); ?>

				</div><!-- /post postcontent -->
                <div class="clear"></div>
                </div>

<?php endwhile; ?>
<?php endif; ?>
    	<?php
			//Check For the Page Navi Plugin
			if (function_exists('wp_pagenavi')) {
   				wp_pagenavi();
			//Show Default Navigation if Page Navi Is Not Installed
			} else { ?>
   				<div id="paginate">
					<div id="paginate-left"><?php previous_posts_link('Newer Posts') ?></div>
					<div id="paginate-right"><?php next_posts_link('Older Posts') ?></div>
				</div><!-- /paginate -->
			<? } ?>
</div><!-- End Main -->
<?php get_sidebar(); ?>
<?php get_footer(); ?>

Muchas gracias.
Un Saludo! 😉