I'm not sure specifically what the issue is from a quick read of your first post, but I have a few comments and ideas for you.

First, don't use $HTTP_SESSION_VARS (which is deprecated), use $_SESSION.

Secondly, it sounds like you have register_globals on, BAD idea. It's a bad (and often disabled) feature of PHP.
http://us2.php.net/register_globals

I would suggest as the cleanest approach, always set your session variables with:
Code:
$_SESSION['name'] = value;
and always read the variables as
Code:
$name = $_SESSION['name'];
and always use a session_write_close(); when you are done manipulating the session data instead of letting PHP do so automatically when the script terminates.

you only have to have any pages start the session and then they can access the variables directly without any extra code, i.e. you don't have to pull $test from $_SESSION, you can just reference $test directly.
You can only do this if register_globals is on. And it's a bad idea because if the session is not actually started, then anyone can inject a value for $test as GET data in the query string, which is great example why register_globals should never be used.