Sorry for the delay in you getting an answer.
How old is your Sureshotgps?
Does it load other courses ok?
If the problem is only with one course, then you will need to try updating the courses on your device:
The update for the Sureshot 8850 is available from :
If the update did not work for you, then you could return it to Sureshotgps for repair - much cheaper than buying a new one.