Opening permalink doesn’t show content on page

It’s not the url from my profile. Can I send you the url?

The link is http://www.chrismochtar.nl/anand/rolandinus/

On the left is the navigation that I have created manually.
These categories all have a Category template, but that is never shown. I always see the Main Index Template.

Category ID 2 is “Activiteiten” which has 4 posts.
Unfortunately the code <?php query_posts('cat=2'); ?> gives no output.

The code get_category_link(2); also doesn’t give the correct output.

The code for Masterclass is:

<?php
$cat8 = $wpdb->get_row("SELECT cat_name FROM $wpdb->categories WHERE cat_id = 8");
$posts = get_posts( "category=8&numberposts=4" ); ?>
<?php if( $posts ) : ?>
<li><a href="#"><?php echo $cat8->cat_name; ?></a>
<ul>
<?php foreach( $posts as $post ) : setup_postdata( $post ); ?>
<li><a>"><?php the_title(); ?></a></li>
<?php endforeach; ?>
</ul>
<?php endif; ?>

But content isn’t shown. It continues to show the Main Index Template instead of the content from the post that is clicked and the category template the post belongs to.