Error message is

cannot load MySQL extension,
please check PHP Configuration.
Documentation

I checked the directories in /etc
and found that

szh@myserver:/$ ls /etc/apache
access.conf conf.d httpd.conf.back httpd.conf.old libexec modules.conf modules.conf.dpkg-old srm.conf
conf httpd.conf httpd.conf-dpkg.netsaint httpd.conf.zdss-backup mime.types modules.conf.dpkg-dist modules.conf.old suggested_corrections
szh@myserver:/$ ls /etc/apache2
conf.d

szh@myserver:/$ ls /etc/php3
apache
szh@myserver:/$ ls /etc/php4
apache cgi cli

seems that there are 2 versions of PHP(php3/php4). 2 versions of apache
(apache/apache2)

When i used apt-get remove to uninstall php3/apach2. the directory still exists.

myserver:/# apt-get remove apache2
Reading Package Lists... Done
Building Dependency Tree... Done
Package apache2 is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 68 not upgraded.
asilog-dev-1:/#

myserver:/etc# apt-get remove php3
Reading Package Lists... Done
Building Dependency Tree... Done
Package php3 is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 68 not upgraded.

and I used apt-get install php4-mysql and pma shtill can not access.

myserver:/etc# apt-get install php4-mysql
Reading Package Lists... Done
Building Dependency Tree... Done
The following NEW packages will be installed:
php4-mysql
0 upgraded, 1 newly installed, 0 to remove and 68 not upgraded.
Need to get 0B/21.2kB of archives.
After unpacking 68.6kB of additional disk space will be used.
Preconfiguring packages ...
Selecting previously deselected package php4-mysql.
(Reading database ... 37521 files and directories currently installed.)
Unpacking php4-mysql (from .../php4-mysql_4%3a4.3.10-15_i386.deb) ...
Setting up php4-mysql (4.3.10-15) ...

pls help me.

more info

myserver:/usr/opt/interbase/db# dpkg -l |grep mysql
ii libdbd-mysql-p 2.9006-1 A Perl5 database interface to the MySQL data
ii libmysqlclient 3.23.56-3 LGPL-licensed client library for MySQL datab
ii libmysqlclient 4.0.24-10 mysql database client library
ii libmysqlclient 3.22.30-4 mysql database client library
ii mysql-client 4.0.24-10 mysql database client binaries
ii mysql-common 4.0.24-10 mysql database common files (e.g. /etc/mysql
ii mysql-doc 3.23.51-0woody mysql database documentation
ii mysql-server 4.0.24-10 mysql database server binaries
ii php4-mysql 4.3.10-15 MySQL module for php4
myserver:/usr/opt/interbase/db# dpkg -l |grep php
rc libphp-adodb 4.10-1 The 'adodb' database abstraction layer for p
rc php3 3.0.18-31 server-side, HTML-embedded scripting languag
ii php4 4.3.10-15 server-side, HTML-embedded scripting languag
ii php4-cgi 4.3.10-15 server-side, HTML-embedded scripting languag
ii php4-cli 4.3.10-15 command-line interpreter for the php4 script
ii php4-common 4.3.10-15 Common files for packages built from the php
rc php4-gd2 4.3.2+rc3-2 GD module (with GD2) for php4
ii php4-imap 4.3.10-15 IMAP module for php4
ii php4-mysql 4.3.10-15 MySQL module for php4
ii php4-pear 4.3.10-15 PEAR - PHP Extension and Application Reposit
ii php4-snmp 4.3.10-15 SNMP module for php4
rc phpmyadmin 2.6.2-3 set of PHP-scripts to administrate MySQL ove