Joe,
Check this out.
http://php.net/manual/en/sqlite.installation.php
It means you have to download sqlite via PECL. It no longer comes with the base PHP as of PHP 5.4.
If you are using a package I would expect that it is not compatible with PHP 5.4 yet so it may be easier to download a 32bit wamp that uses PHP 5.3.x which does come with sqllite automatically.