It means that you have a data error in your Internal Memory. You should try a complete return to factory defaults (hold down 8 key at startup). This will erase ALL stored presets, but should fix the problem.
In a system as old as yours, this probably means that the internal battery has died – they usually last 5-10 years. If this is the case, the above may fix it but it will re-occur. The battery is a internal plugin part that can be purchased from the Eventide Web Store. They are not cheap.
