Likely because you did the stupid thing, which is copying your files from an older copy of Blockland.
You're supposed to install over the old copy, which will overwrite anything old.
If you want the key, just go install Blockland again. The only thing you should ever copy is config. The rest backs up automatically.
i did reinstall. just go host it somewhere adn save the trouble.
for that matter, i installed it directly, and as i said, i think it was overwritten while RTBing a server