mysql-server upgrade errors

[Wybo Dekker]

When I run the update manager, then since a week or so it tells me that 
an error occurred:
E: 
/var/cache/apt/archives/mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.1_i386.deb: 
subprocess new pre-removal script returned error exit status 1

When I run the update manager again, it proposes:
Version 5.1.30really5.0.75-0ubuntu10.1:

   * debian/patches/38_scripts__mysqld_safe.sh__signals.dpatch:
     - Don't trap sighup as it's causing mysqld to refresh while it has
       open connections. (LP: #326768)

And here are the details reported when I let it go:

-------------start of report -------------
Xlib:  extension "RANDR" missing on display ":0.0".
Xlib:  extension "RANDR" missing on display ":0.0".
Preconfiguring packages ...
(Reading database ... 163410 files and directories currently installed.)
Preparing to replace mysql-server-5.0 5.1.30really5.0.75-0ubuntu10 
(using .../mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.1_i386.deb) ...
Xlib:  extension "RANDR" missing on display ":0.0".
Xlib:  extension "RANDR" missing on display ":0.0".
  * Stopping MySQL database server mysqld
    ...fail!
invoke-rc.d: initscript mysql, action "stop" failed.
dpkg: warning - old pre-removal script returned error exit status 1
dpkg - trying script from the new package instead ...
Xlib:  extension "RANDR" missing on display ":0.0".
Xlib:  extension "RANDR" missing on display ":0.0".
  * Stopping MySQL database server mysqld
    ...fail!
invoke-rc.d: initscript mysql, action "stop" failed.
dpkg: error processing 
/var/cache/apt/archives/mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.1_i386.deb 
(--unpack):
  subprocess new pre-removal script returned error exit status 1
Xlib:  extension "RANDR" missing on display ":0.0".
Xlib:  extension "RANDR" missing on display ":0.0".
  * Stopping MySQL database server mysqld
    ...fail!
invoke-rc.d: initscript mysql, action "stop" failed.
  * Starting MySQL database server mysqld
    ...done.
/usr/bin/mysqladmin: connect to server at 'localhost' failed
error: 'Access denied for user 'debian-sys-maint'@'localhost' (using 
password: YES)'
Errors were encountered while processing:
 
/var/cache/apt/archives/mysql-server-5.0_5.1.30really5.0.75-0ubuntu10.1_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install.  Trying to recover:
-------------end of report -------------

 From the above, the problem seems to be the stopping of the mysqld 
deamon. And indeed, I can't stop it by hand either:

root>/etc/init.d/mysql stop
  * Stopping MySQL database server mysqld             [fail]

what might be wrong here? mysql still runs fine.

-- 
Wybo