Read more link doesnt show up

Hi guys!

I am having problems with one of my sites … the template was bought from TM and the problem I am having is that I can not get the read more link to show up. I am just using the simple <!–more–> tag but it doesnt work. The code in index.php goes like this:

<?php get_header(); ?>

	<?php get_sidebar(1); ?>

		<?php if (is_home()) : ?>
		<?php endif; ?>

		<?php if (have_posts()) : ?>
			<?php while (have_posts()) : the_post(); ?>
				<div <?php post_class() ?> id="post-<?php the_ID(); ?>">

					<div class="indent">

						<div class="title">

							<h2><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h2>

							<div class="date">
								<?php the_time('l, F j, Y') ?> ob <?php the_time('H:i') ?>
							</div>

						</div>

						<div class="text-box">
							<?php the_content('Read on...'); ?> 

						</div>

						<div class="link-edit"><?php edit_post_link('Uredi objavo', ''); ?></div>	

					</div>

				</div>
			<?php endwhile; ?>

		<?php else : ?>
			<h2 class="pagetitle">Not Found</h2>
			<p class="center">Sorry, but you are looking for something that isn't here.</p>
			<?php get_search_form(); ?>
		<?php endif; ?>

<?php get_sidebar(2); ?><?php get_sidebar(3); ?>
<?php get_footer(); ?>

Now what could be wrong since this code is the same in almost all templates. Do I maybe have to edit functions.php or something?