It means that your lift pot is out of range. You will need the superword to access the menu to see what the reading is in the system. The unit still should drive, but will not lift and lower.
There was an upgrade a few years ago on the Easi Trucks to a new optical switch vs a straight pot. If this was not done you'd be better off just replacing the handle with a new one with the upgraded guts. You will still need the superword to relearn the handle