I'd like to think I know what I'm doing in a Unix shell but maybe not.

I made a mistake in a configuration file for MySQL, so I decided to just uninstall it and then reinstall it, so I did:

sudo apt-get --purge remove mysql-server mysql-server-5.0 mysql-client

The files were deleted, so I then tried to install it, but it didn't ask me for a root password or anything else, so I uninstalled it using the above command again and then did

sudo rm -rf /etc/mysql
sudo rm /etc/init.d/mysql
sudo rm -rf /var/lib/mysql*

I then restarted the computer then installed it again:

sudo apt-get install mysql-server mysql-client

It asked for a root password, and everything looked like it would work, until I saw this:

$ sudo apt-get install mysql-server mysql-client
Reading package lists... Done
Building dependency tree

Reading state information... Done
The following extra packages will be installed:
  mysql-server-5.0
Suggested packages:
  tinyca
The following NEW packages will be installed:
  mysql-client mysql-server mysql-server-5.0
0 upgraded, 3 newly installed, 0 to remove and 1 not upgraded.
Need to get 0B/27.4MB of archives.
After this operation, 86.7MB of additional disk space will be used.
Do you want to continue [Y/n]? y
WARNING: The following packages cannot be authenticated!
  mysql-server-5.0 mysql-client mysql-server
Authentication warning overridden.
Preconfiguring packages ...
Can't exec "/tmp/mysql-server-5.0.config.28101": Permission denied at /usr/share/perl/5.10/IPC/Open3.pm line 168.
open2: exec of /tmp/mysql-server-5.0.config.28101 configure  failed at /usr/share/perl5/Debconf/ConfModule.pm line 59
mysql-server-5.0 failed to preconfigure, with exit status 255
Selecting previously deselected package mysql-server-5.0.
(Reading database ... 160284 files and directories currently installed.)
Unpacking mysql-server-5.0 (from .../mysql-server-5.0_5.0.51a-24+lenny5_amd64.deb) ...
Selecting previously deselected package mysql-client.
Unpacking mysql-client (from .../mysql-client_5.0.51a-24+lenny5_all.deb) ...
Selecting previously deselected package mysql-server.
Unpacking mysql-server (from .../mysql-server_5.0.51a-24+lenny5_all.deb) ...
Processing triggers for man-db ...
Setting up mysql-server-5.0 (5.0.51a-24+lenny5) ...
Stopping MySQL database server: mysqld.
/var/lib/dpkg/info/mysql-server-5.0.postinst: line 144: /etc/mysql/conf.d/old_passwords.cnf: No such file or directory
dpkg: error processing mysql-server-5.0 (--configure):
 subprocess post-installation script returned error exit status 1
Setting up mysql-client (5.0.51a-24+lenny5) ...
dpkg: dependency problems prevent configuration of mysql-server:
 mysql-server depends on mysql-server-5.0; however:
  Package mysql-server-5.0 is not configured yet.
dpkg: error processing mysql-server (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 mysql-server-5.0
 mysql-server
E: Sub-process /usr/bin/dpkg returned an error code (1)

Now I can't seem to figure out what to do. I just want to get a clean MySQL installation at this point. I'm running the latest stable release of Debian.

All help is appreciated—thanks!

Edit: I looked at this similar question, which suggests that I uninstall mysql-common, but when I try to do so I see:

The following packages will be REMOVED:
  apache2 apache2-mpm-prefork apache2-utils apache2.2-common git-svn libapache2-mod-php5 libapache2-mod-python libapache2-svn libaprutil1
  libdbd-mysql-perl libdbd-mysql-rubygem libmysql-ruby libmysql-ruby1.8 libmysql-rubygem libmysqlclient15-dev libmysqlclient15off librdf-perl librdf0
  libserf-0-0 libsvn-perl libsvn1 mysql-client-5.0 mysql-common mytop ndn-apache22-php5 ndn-apache22-svn ndn-interpreters ndn-lighttpd
  ndn-netsaint-plugins ndn-perl-modules ndn-php5-cgi ndn-php5-xcache ndn-php53 ndn-php53-suhosin ndn-rubygems php5 php5-mcrypt php5-mysql proftpd
  proftpd-mod-mysql python-django python-mysqldb python-subversion python-svn subversion subversion-tools trac zendoptimizer
0 upgraded, 0 newly installed, 48 to remove and 1 not upgraded.

Eeek! Any suggestions?