Most likely, you're seeing this message because Your Admin made a programming mistake somewhere. Rest assured that the server has already sent him a message detailing the error of his ways in far more detail than you would believe, and that he'll get on fixing it as soon as possible.
If you want, feel free to send him an email, especially if this is the first time you've tried something or if there's just been an upgrade. And if you're feeling adventurous, you're more than welcome to re-enter the database, where the problem could already be fixed. You might also have to log out if the server is really confused. Ghosts lurk these machines.
Your Admin
Email: admin@example.com