Any ideas why my thread is invisible?

[Cap'n Steve]

I'm developing a hack that needs to create a new thread. The problem is that the first post in the thread is invisible. You can only see it while replying to the thread. Here's the code I'm using:

PHP Code:

$threads = explode(',', $target['newthread']);
foreach ($threads AS $thread) {
    if (is_numeric($thread)) {
        build_new_post('thread', fetch_foruminfo($thread), array(), 0, $newpost, $errors);
    }
}