vB5 API help - latest / trending posts list only returns if < 5 days

[Beergeeksf]

I created a simple PHP script that loads the vB5 API and generates a simple JSON list of the trending posts. (See sample code below). The problem is that I can't get the scripts to generate anything for more than a couple days. Ideally I'd like to get the trending posts in the last 7 days, last 31 days, etc. But it I go over 3-5 days, nothing is returned. Any suggestions?

Sample code to load the vB5 API, and get the last 20 days of posts:

$vbpath = $_SERVER['DOCUMENT_ROOT'];
define('CSRF_PROTECTION', false);
require_once($vbpath . '/includes/vb5/autoloader.php');
vB5_Autoloader::register($vbpath);
vB5_Frontend_Application::init('config.php');

$api = Api_InterfaceAbstract::instance();

$search_json = '{"channel":["15"],"starter_only":1,"date":{"from":"'7'"},"sort":{"lastcontent":"desc"},"view":"","exclude_type":["vBForum_PrivateMessage"]}';

$threads = vB_Api::instanceInternal('search')->getInitialResults($search_json, 30, 1);      

$i = 0;
$thread_returns = array();

if (!isset($threads['errors']) AND !empty($threads['results'])) {
  //let's get views too
  $threads['results'] = vB_Api::instanceInternal('node')->mergeNodeviewsForTopics($threads['results']);

  foreach ($threads['results'] as $tid => $thread_details) {
    $i++;
    $thread_returns['results'][$i] = array(
      'title'         => $thread_details['content']['title'],
      'publishdate'   => $thread_details['content']['publishdate'],
      'channeltitle'  => $thread_details['content']['channeltitle'],
      'description'   => $thread_details['content']['description'],
      'userid'        => $thread_details['content']['userid'],  
      'authorname'    => $thread_details['content']['authorname'],
      'uniqueid'      => $thread_details['content']['nodeid']
    );

    //Get author profile page
    if($user_info = vB_User::fetchUserinfo($thread_details['content']['userid'], 0, false, false)) {
      $thread_returns['results'][$i]['user_bbprofileurl'] = vB5_Route::buildUrl('profile|bburl', array('userid' => $thread_details['content']['userid'], 'username' => $thread_details['content']['authorname']));
    }
    
    //vB5_Route::buildUrl -- build out the URL to the post
    $thread_returns['results'][$i]['postlink'] = vB5_Route::buildUrl(
      $thread_details['routeid'] . '|fullurl',
      array(
        'nodeid' => $thread_details['nodeid'],
        'title' => $thread_details['title']
      )
    );

    //vB5_Route::buildUrl -- build out the URL to the channel
    $thread_returns['results'][$i]['channellink'] = vB5_Route::buildUrl( $thread_details['content']['channelroute'] . '|fullurl' );

    //Add in the views and votes
    $thread_returns['results'][$i]['views'] = $thread_details['content']['views'];
    $thread_returns['results'][$i]['votes'] = $thread_details['content']['votes'];

  }
}
$thread_returns['totalRecords'] = count($thread_returns['results']);
$thread_returns['searchJSON'] = $search_json;
$thread_returns['days'] = $num_days;

if ($thread_returns['totalRecords'] > 0) {
  header('Content-Type: application/json');
  echo json_encode($thread_returns);
} else {
  var_dump($thread_returns);
}

If I change the $search_json code above 5 days, nothing is returned, no error is create, just blank output.

Any help is greatly appreciated.

Cheers,
Jeff