Loop last posts of Cat… [do problem when this on post)

Hello,
I have loops of lasts post of categories Specific.
They in the footer, show in all page in the site (That’s how they should be at least)

Is It work in the index and other places, but in posts, and pages, is it show Details of the post where I am or not show all.

the code of i use:

<!-- Start the Loop. -->
 <?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
 <?php if ( in_category('5') ) { ?>
<p><a href="<?php the_permalink() ?>" title="<?php the_title_attribute(); ?>"><?php the_title(); ?></a> - <?php echo get_the_excerpt(); ?>... more on <?php the_category(', '); ?></p>
 <?php } else { ?>
 <?php } ?>

 <?php endwhile; else: ?>
 <p>posts not found, sorry.</p>
 <?php endif; ?>
 <!-- Stop the Loop. -->

Hope can Understand my english, and can help me..
I appreciate very much help in this thing.