1) The country list on your registration page and the country list on the checkout page don't match.
on the registration page, the Country list passes the full country name for the value, for example:
<option value="United States"
on the checkout page, the country list uses the Abbreviations:
<option value="US"
the values for the two lists will needs to use the same conventions, either use abbreviations for both, or use the ful countrry name.
2) when a user logs in, their ID is stored in a session variable named SecurityAssist_UserID. When the order summary is stored in the database, that ID value is stored in the OrderUserID column o the users table.
to show the orders for the logged in user, add a where statement to the recordsets on the order history pages to filter the OrderUserID column on the SecurityAssist_UserID session variable.
the Order History tutorial talks about this throughout:
http://www.webassist.com/community/tutorials/view_tutorial.php?tid=17
in the tutorial, the session is named UserID, but your login page creates the session as SecurityAssist_UserID