You need to enable either the SQLite3 or PDO_SQLite extension for the profiler to run properly.

After installing Symfony 2 instead of viewing your website, you see this error message :

You need to enable either the SQLite3 or PDO_SQLite extension for the profiler to run properly.

It probably means you need to install the sqlite extension for php

apt-get install php5-sqlite

restart apache and that should to the tricks.