What is the name of the file which you used?
There's two sample data bases. One is the data warehouse, with one schema. The other is gosales. It has 4 schemas: gosales, retailers (gort), Marketing (gomr), and human resources (gohr). You can also tell the difference in that the non-data warehouse db has a separate table for order header and order details.
I have not memorized the tables of either but I suspect that you have gosales rather than the data warehouse but there isn't sufficient information to make a definitive statement.