Fatal error: Cannot use object of type stdClass as array in **/index.php on line 18
The code was working fine recently, but now, I suspect due to a PHP upgrade, is rendering the above referenced error message. I'm not really sure how to rectify something such as this, so any help would be greatly appreciated so I can get things running once again.

Line 18 is within the below code, it begins with "$first_tweet."

PHP Code:
if(isset($_POST['firstuser'])) {
$first_user $_POST['firstuser'];
$twitter = new Twitter($requestusername$requestpassword);
$user1errorstatus false;
$results false;
$user_first_info json_decode($twitter->showUser("json"$first_user));
$user_first_info->error)) {
$user1errorstatus true;
$user1errorstatus == false) {
$num_tweets $user_first_info->statuses_count;
$inpage ceil($num_tweets 20);
$userstats $twitter->getUserTimeline($first_user$inpage);
$userstats json_decode($userstats);
$num_stats count($userstats) - 1;
$first_tweet $userstats[$num_stats]->text;
$results true;