Everything neilo posted is spot on.
However, even if you did create the recordset by hand, it still would not work. Dreamweaver relies on the connection to the mysql server to get information about the database like Table Names, and Names for the columns.
This information is used when creating the binding panel. Without a connection to the database through the testing server, Dreamweaver cannot create the dynamic data bindings for the recordset columns that will be used in add to cart from recordset button. Without the dynamic bindings to the recordset columns, you cannot bind the cart columns to them.