We would ask that you verify the name of the database as stated in /includes/global.inc.php matches the actual name of the database as seen in your hosting account's control panel (Cpanel?). Also, if the database tables have a prefix, make sure it matches what is given in global.inc.php.
Not allowing a table column's name as the "key" to fetch the row's contents usually means the requested table doesn't exist, or CubeCart is using a table prefix when it shouldn't, or v.v.