Masz tutaj problem z cytatami. Zmień
$sqlCmd = sprintf("UPDATE account.account SET coins = coins +100 WHERE id = '.$_SESSION['user_id'].'"
z
$sqlCmd = "UPDATE account.account SET coins = coins +100 WHERE id = '".$_SESSION['user_id']."'"
Masz tutaj problem z cytatami. Zmień
$sqlCmd = sprintf("UPDATE account.account SET coins = coins +100 WHERE id = '.$_SESSION['user_id'].'"
z
$sqlCmd = "UPDATE account.account SET coins = coins +100 WHERE id = '".$_SESSION['user_id']."'"