Query Crash ?

Hi,

I’m using query_posts on my archive, category, tags etc. pages for controlling more parameters like number of displayed posts for different things. I noticed lately something weird. When for an example i set category page to show 1 post per page and go to the page 3 (sometimes 4 or 5) the query seems to crash. No posts are displayed, category title (or month – depends on what page I am) dissappear … I tried to echo $query_string for debugging and for the first pages it displays everything fine but when query crashes it dissappears with everything else. Any ideas or similar issues ?

I’m using standard loop :

<?php query_posts($query_string.'&posts_per_page='.$archive_postnum.'&paged='.$paged); ?>
<?php if (have_posts()) : ?>

Thanks

P.S this happens on all wordpress versions including 2.8.6