I have added a custom field to some posts called 'frontpagerank'
Then shouldn't the WP_Query args reference that key then, eg.
'meta_key' => 'frontpagerank'
If i follow, you want to check for posts that have this key, and you're expecting a numeric value, so i'll naturally assume you don't want posts with this key(but an empty value).
$the_query = new WP_Query(array( 'meta_key' => 'frontpagerank', 'meta_value' => '', 'meta_compare' => '!=', 'orderby' => 'meta_value_num' ));
Or if you specifically want to check for posts with that meta_key where the value is above say 0, you could do..
$the_query = new WP_Query(array( 'meta_key' => 'frontpagerank', 'meta_value' => '0', 'meta_compare' => '>', 'orderby' => 'meta_value_num' ));
You can read info on the meta parameters here.
Info on order by to, since i added that into the above to.. ;)
..any parameters you see listed for query_posts can be used inside WP_Query
Then all you need do is loop over that data like you had earlier..
// Note i made the correction you commented on, yes that's need to match
while( $the_query->have_posts() ) : $the_query->the_post();
// do whatever
Hope that helps.