using Plugin to display SQL result in postbit

[mcdull]

All I need is to display a value return from SQL in the Postbit.

I use a plugin to hook into the postbit_display_start using

<?php
$post_reps=$db->query_first("SELECT COUNT(userid) as countrep FROM " . TABLE_PREFIX . "reputation WHERE postid = " . $postid );

$rep_given = $post_reps['countrep'];

eval('print_output("' . fetch_template('postbit') . '");');
?>

but the page is totally blank. Can anyone please help me?
Thanks

problem temporary solved.