#08S01Bad handshake


My RoR webapp was working fine until this morning. I run the App on a
Ubuntu 10.04.4 LTS server and nothing seems to have changed during the
night but now I get a #08S01Bad handshake everytime the App tries to
access MySQL.

Apache is running fine
The MySQL server is running fine as I can access it via phpMyAdmin and
via an Access frontend

I googled a lot but nothing helped much until now.

Any hint would be appreciated!