Must be a problem with the 'sailors' DSN then. I assume the book has steps to create the DSN? Did you have any problems setting it up?
You can test the DSN using a udl file. Just create a new file called anything.udl, then double-click it and a "Data Link Properties" dialog will appear. On the Connection tab, under "Specify the source of data", choose the "Use data source name" option and select the sailors dsn from the drop-down. The hit the 'Test Connection' button and see what happens!