Comment 15 for bug 522185

When you try to upgrade, do you have an error message like that :
"Setting up mysql-server-5.1 (5.1.37-1ubuntu5.1) ...
 * Stopping MySQL database server mysqld
   ...done.
 * Starting MySQL database server mysqld
   ...fail!
invoke-rc.d: initscript mysql, action "start" failed.
dpkg: error processing mysql-server-5.1 (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of mysql-server:
 mysql-server depends on mysql-server-5.1; however:
  Package mysql-server-5.1 is not configured yet.
dpkg: error processing mysql-server (--configure):
 dependency problems - leaving unconfigured
Setting up apache2.2-bin (2.2.12-1ubuntu2.2) ...
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          Setting up apache2-utils (2.2.12-1ubuntu2.2) ...
Setting up apache2.2-common (2.2.12-1ubuntu2.2) ...

Setting up apache2-mpm-prefork (2.2.12-1ubuntu2.2) ...
 * Starting web server apache2
   ...done.

Setting up apache2 (2.2.12-1ubuntu2.2) ...

Setting up dpkg-dev (1.15.4ubuntu2.1) ...
Errors were encountered while processing:
 mysql-server-5.1
 mysql-server
E: Sub-process /usr/bin/dpkg returned an error code (1)"

Do you really need mysql on this computer (to know if it is possible to test to remove and reinstall mysql package) ? You should save your databases before removing mysql)