Have modified the query to the new format:
// ############### HIDE (LOCK) HACK ###################
$DB->simple_construct( array( 'select' => 'author_name',
'from' => 'posts',
'where' => "topic_id=".$this->topic['tid'],
) );
$DB->simple_exec();
while ($i = $DB->fetch_row())
{
$allposters[] = $info['author_name'];
}
$DB->simple_shutdown_exec();
// ############### HIDE (LOCK) HACK ###################
But something is stopping it from getting the allposters variable