Here is in brief what's going on.
Last Friday (CET), big hardware troubles started on the server which db4free.net runs on. The server was unavailable and I didn't manage to start it up again by myself. I files a support ticked to my server provider, and by Saturday afternoon, the server was accessible again. Everything seemed to look fine, but Sunday, shortly after midnight, the same troubles started again.
My server provider gave me a new server, and thankfully, managed to get the old server to start up again. I backed up the user databases and copied them to the new server, so no - or at least almost no - data should be lost.
It will take me some time to migrate the entire service to the new server, so please be patient. I also want to use this "opportunity" to start offering MySQL 5.5, so my plan is to make the old server available on a different port, and start the entire service over on a fresh and clean MySQL 5.5 instance. This will mean that users will have access to their data (probably for the next 2 months or so, until I shut down the MySQL 5.1 server), but in order to use the new server, everybody will have to register a new account again. These are my current plans, and I hope to have the new db4free.net fully up again by upcoming Friday (March 26).
Please apologize the inconveniences. However, it's again a good opportunity to remember that db4free.net is a testing service with no warranties and that users should keep backups of all data they really need!