I don't think your problem is that the design is wider than it is tall. The design should load onto your flashdrive in a rotated position automatically, because otherwise virtually no one would be able to stitch this design, unless they had a minimum 8x8 hoop.
Are you sure you have the correct format? If so, I would contact the company you bought the design from, because something is wrong here. Perhaps, your machine can't recognize an incorrect format, or a corrupted file.