Build_new_post only works if you are logged in?

[x3sphere]

This is the code I have:

PHP Code:

            $rforuminfo = fetch_foruminfo($forumid);
            $newpost = array(
                'userid' => $userid,
                'username' => $comment_username,
                'message' =>  $comment_text,
                'thread' => $threadid
);
            $threadinfo['threadid'] = $threadid;
            build_new_post('Post', $rforuminfo, $threadinfo, array(), $newpost, $errors);
                    if (sizeof($errors) > 0)
        {
            $error_text = construct_errors($errors);
            echo $error_text;
        }
            build_forum_counters($forumid); 


Works great, but only if you are logged into the forum. When I'm not logged in, it spits out this:

That username is already in use. If you are x3sphere and you have forgotten your password, click here.
The string you entered for the image verification did not match what was displayed.

Any ideas on to get this working while you are logged out?