PDO Failing

Trying to install piwik on apache, but getting the following response:

Piwik requires either the mysqli extension or both the PDO and pdo_mysql extensions.
    On a Linux server you can compile php with the following options: 
    In your php.ini, add the following lines: 
    After making this change, restart your web server.

I have included those lines in /etc/php5/apache2/php.ini, I have restarted the daemon and the computer and I have ran php -l | grep PDO which outputs:

    PDO support => enabled
    PDO drivers => mysql
    PDO Driver for MySQL => enabled

which seems to me to indicate that it should be working?!

Ubuntu 12.04
PHP 5.3.10
Mysql 5.5.28

Php.ini -> https://dl.dropbox.com/u/207196/php.ini

Phpinfo() -> http://telly.mildfuzz.com/phpinfo.php

Piwik installation page -> http://telly.mildfuzz.com/piwik/index.php?action=systemCheck&trackerStatus=500