After upgrade, exerpts of posts not showing

After upgrading to WP 2.0 the code below has stopped working. I have it in the index file, and what it does is show exerpts of posts for specific categories, and full content for other categories on the home page. After the upgrade, it now only shows full posts, which I do not want.

Anyone have any ideas why the code no longer works with 2.0?

<?php if(in_category(1) || in_category(5)) : ?>
<?php the_excerpt(); ?>
<?php else : ?>
<?php the_content(); ?>
<?php endif; ?>