In a Symfony2 project, you can configure the databases connections at the app/config/parameters.ini file. Documentation states that you can use, among others, sqlite3 PDO dr
Mainly the file path or the file path permisssion will have issue.
In config.yml, set path to full path like
/home/{name}/NB/PHP/Symfony/test/src/Database/data.db3
Dont give %database_path% or what ever. Try this it will work.
If it works you can give as
%kernel.root_dir%/../src/Database/%database_path%
Also check sqlite is ok by
phpinfo(INFO_MODULES);
In view/output you can see pdo_sqlite and its version.