note 9655 added to session_start

Please help me!! I really want to pass form variables to session variables, but can't figure it out. I have tried some of the simple examples provided here, and they all work provided that you hard code the session variable value. But what I want is to have a form submit the values, and when I try a always get an error: Warning: Undefined variable etc... Can anyone code a simple example of this working and post it? It would be greatly appreciated. http://www.php.net/manual/function.session-start.php