Here's an easy template hack:
1. Open your template directory, located in wp-content/templates/TEMPLATE-NAME, where TEMPLATE-NAME is the name of your template.
2. Look for a page named tag.php. If it exists, open it in your HTML editor. If it does not exist, open the page named archive.php.
3. Make a backup copy of your old tag.php or archive.php file and put it someplace safe.
4. Look for the line of code that reads: <?php endwhile; ?>
5. Directly above that line, add this:
<?php if (function_exists('sociable_html')) {
echo sociable_html();
} ?>
6. Save the page.
7. Upload the new tag.php or archive.php page to your theme directory, replacing the old one.
If all goes well, the tag page will now show the links. If not, replace the new version of tag.php or archive.php with your backup copy.