This happened to me when I loaded the non-crash version of the game and tried to use my old save game with it. It told me each time that I re-entered the game that my registration code needed to be entered. I had 65 villagers at the time I saved the game from the previous version, and WAS registered before I loaded the new version. After I reloaded, all my villagers were gone. I went back to the original version of the game and my villagers were there, but my stats were crazy, It said I had a few billion food and had been playing for 5 million hours or so. Also, several of the tech items went away (a couple of the huts and the idol and the stones). I had completed the first 9 puzzles and had all of the tech. I finally deleted everything from the handheld and started over from scratch. Everything was fine then, except for losing the game that was well in progress.

I have a Tungsten E.