GPS route number error message

I have tried to put the Delaney Geocache route into my GPS but it says that it is invalid. Here is the error,
The route Delaney Geocache has an invalid route number (23). Your Magellan SporTrak uses route numbers 1 – 20.
Edit your routes so that all route numbers are within this range."
I do not know how to handle this. Can anyone help?

