RS interfers with get posts

Hi I am using this code for a page on my site. Essentially I want it to show posts from a category to contributors and higher. However for some reason contributors get a white page instead of the posts (or the else message). The category is visible to contributors, and if I turn RS off contributors can see the posts.

<?php
if ( current_user_can('edit_posts') ) {
query_posts('cat=11334&showposts=2');
while (have_posts()) : the_post();
?><h4>
<?php
the_title();
?></h4>
<?php
the_content(); ?>
<hr><?php
endwhile;
} else {
echo 'Find out how you can become a contributor by <a href="">Clicking Here</a>';
}?>

https://www.ads-software.com/extend/plugins/role-scoper/