Permalink and problem with including posts on a external webpage

I want to activate permalink on my blog however everytime I do, my standalone php pages lose the ability to show posts from a certain catagory.

Soon as I set it back to default it works again.

The code I am using on my stand along php pages is below.

What am I doing wrong/missing. Many Thanks

<?php query_posts($query_string . '&cat=7'); ?>
<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>

 <div class="post">

 <!-- Display the Title as a link to the Post's permalink. -->
 <h4><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h4>

 <!-- Display the date (November 16th, 2009 format) and a link to other posts by this posts author. -->
 <small>Published <?php the_time('F jS, Y') ?> by <?php the_author_posts_link() ?></small>

  <div class="entry">
    <?php the_content(); ?>
  </div>
	 <hr style="color: #000000"></hr>
<p></p>
 </div> <!-- closes the first div box -->

 <?php endwhile; else: ?>
 <p>Sorry, no posts matched your criteria.</p>
 <?php endif; ?>

		<p>&nbsp;</p>
		<h3>Past One Off Events<a name="PastEvents"></a></h3>
		<p>&nbsp;</p>
<?php query_posts($query_string . '&cat=8'); ?>
<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>

 <div class="post">

 <!-- Display the Title as a link to the Post's permalink. -->
 <h4><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h4>

 <!-- Display the date (November 16th, 2009 format) and a link to other posts by this posts author. -->
 <small>Published <?php the_time('F jS, Y') ?> by <?php the_author_posts_link() ?></small>

  <div class="entry">
    <?php the_content(); ?>
  </div>
	  <hr style="color: #000000"></hr>
<p></p>
 </div> <!-- closes the first div box -->

 <?php endwhile; else: ?>
 <p>Sorry, no posts matched your criteria.</p>
 <?php endif; ?>