query_posts for category

I am working on a theme that uses query_posts. For the category page, I am trying to show posts that are just in that category. I tried the following code that I found on this page but it does not work.

<?php $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;

// Replace any spaces in the title with dashes
$title_slug = strtolower(str_replace( " ", "-" , the_title_attribute('echo=0') ) );
// Get the category object by using our new title slug
$id_obj = get_category_by_slug($title_slug);
// Get the category id so that we can use that in the query
$cat_id = $id_obj->term_id;

query_posts('post_type=post&posts_per_page=5&cat='.$cat_id.'&paged=' . $paged); ?>

Any suggestions? I would really appreciate it.