Solution

Simply follow these 4 steps to fix the problem:

1. Open the topic-tags.php file of your template. You may download it via a FTP program if you do not have it saved on your computer.
2. Find this code in the file:
   [php]<?php if ( $public_tags ) : ?>
   <div id="othertags">
   <p><?php _e(‘Tags:’); ?></p>
   <ul id="yourtaglist">
   <?php foreach ( $public_tags as $tag ) : ?>
   <li id="tag-<?php echo $tag->tag_id; ?>_<?php echo $tag->user_id; ?>"><a href="<?php bb_tag_link(); ?>" rel="tag"><?php bb_tag_name(); ?></a> <?php bb_tag_remove_link(); ?></li>
   <?php endforeach; ?>
   </ul>
   </div>
   <?php endif; ?>

   <?php if ( !$tags ) : ?>[/php]

3. Replace it with the following code:
   [php]<p><?php _e(‘Tags:’); ?></p>

   <?php if ( bb_get_topic_tags() ) : ?>

   <?php bb_list_tags(); ?>

   <?php else : ?>[/php]

4. Save the file and upload it to your server. You have now successfully fixed the issue!

You can see these changes made in the default theme in the trac here. I hope that this tutorial would have helped you. If you have any problems, you may ask them in the comments form below.