RSS feed for tags broken

Hi!

Last week, I have updated my installation to WordPress 2.5 beta1.

I experienced no problems until now…

On the archive page, I have a meta section that uses the following code

<?php if (is_category()) { ?>

<h2 class="archive_name"><?php echo single_cat_title(); ?></h2>        

<div class="archive_meta">

<div class="archive_feed">
<?php $cat_obj = $wp_query->get_queried_object(); $cat_id = $cat_obj->cat_ID; echo '<a href="'; get_category_rss_link(true, $cat, ''); echo '">RSS Feed für diese Kategorie</a>'; ?>
</div>

<div class="archive_number">
Diese Kategorie enthält <?php $cat = get_the_category(); $cat = $cat[0]; echo $cat->category_count; ?> Artikel.
</div>
</div>        		

<?php } elseif (is_tag()) { ?>
<h2 class="archive_name"><?php echo single_cat_title(); ?></h2>
<div class="archive_meta">

<div class="archive_feed">
<a href="<?php echo get_tag_feed_link(get_query_var('tag_id')); ?>">
RSS Feed zu diesem Schlagwort.</a>
</div>

<div class="archive_number">
<?php $tag = $wp_query->get_queried_object(); echo $tag->count; ?> Artikel wurden mit diesem Schlagwort markiert.
</div>
</div>

for displaying the links to the RSS feeds of the specific category or tag (and for counting the number of posts inside the category and tag).

The RSS feed for a category works fine (and the number of posts are counting correctly), but the RSS feed for tags does not work anymore.

The function echo get_tag_feed_link outputs the correct link, but the provided feed is empty.

Any ideas?