Unpacking mysql-server-5.1 (from .../mysql-server-5.1_5.1.61-0ubuntu0.11.04.1_i386.deb) ...
Processing triggers for ureadahead ...
ureadahead will be reprofiled on next reboot
Processing triggers for man-db ...
Setting up mysql-server-5.1 (5.1.61-0ubuntu0.11.04.1) ...
mysql stop/waiting
invoke-rc.d: unknown initscript, /etc/init.d/mysql not found.
dpkg: error processing mysql-server-5.1 (--configure):
 subprocess installed post-installation script returned error exit status 100