Small problem with PHP-PDO-Sqlite when creating a DB file (driver not found)

I developed an application to export an Sql DB stored at phpmyadmin to Sqlite DB to be used in an Android App. The application was working perfectly until recently but it stopped working after some upgrades in other sections of the website (the original code of the broken application was not changed). When the user tries to use the application, there is a PDO error (" could not find driver "). As phpinfo() indicates (see attached file), the pdo_mysql module is installed.