Undefined property: stdClass - php

Question

I'm getting the following error on these lines
Notice: Undefined property: stdClass::$id on line 36
Notice: Undefined property: stdClass::$id on line 40
Notice: Undefined property: stdClass::$screen_name on line 40
Line 36:
$vOAuth1 = mysql_query("SELECT * FROM `atwitter_oauth_users` WHERE `oauth_provider` = 'twitter' AND `oauth_uid` = '{$oUserInfo->id}'"); // searching for user in database
Line 40:
mysql_query("INSERT INTO `atwitter_oauth_users` (`oauth_provider`, `oauth_uid`, `username`, `oauth_token`, `oauth_secret`) VALUES ('twitter', {$oUserInfo->id}, '{$oUserInfo->screen_name}', '{$aAccessToken['oauth_token']}', '{$aAccessToken['oauth_token_secret']}')");
This is the whole code:
<?php
ini_set('display_startup_errors',1);
ini_set('display_errors',1);
error_reporting(-1);
require_once('inc/header.php');
require_once('inc/twitteroauth.php');
global $sConsumerKey, $sConsumerSecret;
session_start();
if (! empty($_GET['oauth_verifier']) && ! empty($_SESSION['oauth_token']) && ! empty($_SESSION['oauth_token_secret'])) {
} else { // some params missed, back to login page
header('Location: http://www.domain.com/livetweeter/tw_login.php');
echo "parameters missed";
}
$oTwitterOauth = new TwitterOAuth($sConsumerKey, $sConsumerSecret, $_SESSION['oauth_token'], $_SESSION['oauth_token_secret']);
$aAccessToken = $oTwitterOauth->getAccessToken($_GET['oauth_verifier']); // get access tokens
$_SESSION['access_token'] = $aAccessToken; // saving access token to sessions
$oUserInfo = $oTwitterOauth->get('account/verify_credentials'); // get account details
if(isset($oUserInfo->error)){
header('Location: http://www.domain.com/livetweeter/tw_login.php'); // in case of any errors - back to login page
echo "error";
} else {
global $sDbName, $sDbUserName, $sDbUserPass;
$vLink = mysql_connect($sDbHost, $sDbUserName, $sDbUserPass);
mysql_select_db($sDbName);
$vOAuth1 = mysql_query("SELECT * FROM `atwitter_oauth_users` WHERE `oauth_provider` = 'twitter' AND `oauth_uid` = '{$oUserInfo->id}'"); // searching for user in database
$aOauthUserInfo = mysql_fetch_array($vOAuth1);
if (empty($aOauthUserInfo)) { // if user info not present - add them into database
mysql_query("INSERT INTO `atwitter_oauth_users` (`oauth_provider`, `oauth_uid`, `username`, `oauth_token`, `oauth_secret`) VALUES ('twitter', {$oUserInfo->id}, '{$oUserInfo->screen_name}', '{$aAccessToken['oauth_token']}', '{$aAccessToken['oauth_token_secret']}')");
$vOAuth2 = mysql_query("SELECT * FROM `atwitter_oauth_users` WHERE `id` = '" . mysql_insert_id() . "'");
$aOauthUserInfo = mysql_fetch_array($vOAuth2);
} else {
mysql_query("UPDATE `atwitter_oauth_users` SET `oauth_token` = '{$aAccessToken['oauth_token']}', `oauth_secret` = '{$aAccessToken['oauth_token_secret']}' WHERE `oauth_provider` = 'twitter' AND `oauth_uid` = '{$oUserInfo->id}'"); // update tokens
}
$_SESSION['oauth_id'] = $aOauthUserInfo['id'];
$_SESSION['oauth_username'] = $aOauthUserInfo['username'];
$_SESSION['oauth_uid'] = $aOauthUserInfo['oauth_uid'];
$_SESSION['oauth_provider'] = $aOauthUserInfo['oauth_provider'];
$_SESSION['oauth_token'] = $aOauthUserInfo['oauth_token'];
$_SESSION['oauth_secret'] = $aOauthUserInfo['oauth_secret'];
mysql_close($vLink);
header('Location: http://www.domain.com/livetweeter/index.php');
echo "we've got an error";
}
if(!empty($_SESSION['oauth_username'])){
header('Location: http://www.domain.com/livetweeter/index.php'); // already logged, back to our main page
echo "this is an error";
}
?>
Note: I know I shouldn't be using mysql_query - I'll sort that once I have to script working.