If the system says this message, one of two conditions may have occurred:
1. The time allowed to enter your information has expired (with maximum 30 minutes break). In this case, the screen shall give you an option "Click here if you wish to restart the registration" to restart the registration.
2. You clicked the back button after you had already completed your registration. Unless you wish to register another person, you will not need to do anything and a confirmation should be sent to you. The screen message will also give you an option to add another participant if you wish to do so.