you are trying to use a recordset value, but the recordset does not have any filtering applied, this will only use the first in the table.
a better way to do this is to edit the login page to store the users name in a session at login.
on the login page, open the server behaviors panel, window -> Server Behaviors.
in the list of server behaviors, double click the security assist authenticate user server behavior.
click next till you get to the third page of the authenticate user behavior. Here, you can select columns to store in session variables when the user logs in, select the users name column.
On the cart page, use the users name session variable to display their name.