After upgrading Xubuntu 11.10 to 12.04, I had the same problem of #27, solved creating the empty /etc/apparmor.d/local/usr.sbin.mysqld .
After upgrading Xubuntu 11.10 to 12.04, I had the same problem of #27, solved creating the empty /etc/apparmor. d/local/ usr.sbin. mysqld .