IP Address not consistent with customer number

What does "Sorry, Your IP Address is not consistent with the Customer Number you entered" mean?

That message means that your account is setup as a Registration account and the customer number you entered needs to be entered on a machine whose IP is in our system.

If you think that your IP is already entered into our system, go to http://ars.sirs.com/ipaddress.html to display your IP address. Then contact Customer Service and give them your IP address to see if it is entered, or to have it added if it is not already present.