there is also a php 5.3 version, if you have that version of php installed php53-pdo, but don't install that otherwise as the upgrade breaks loads of stuff.
there is a php-mssql module as well which might be handy.
Note that pdo_mysql != pdo_sqlite. It does not appear that it is loading the PDO MySQL driver that Vanilla is looking for. It wouldn't be the first time that PDO-MySQL hasn't worked properly on MAMP.
I know with WAMP it has pre-compiled all of the binaries for you; it might not work in your specific environment because of this. I would recommend compiling PHP and the PDO-mySQL extension manually to make sure it will work.
Best Answer
yum install php-pdothere is also a php 5.3 version, if you have that version of php installed php53-pdo, but don't install that otherwise as the upgrade breaks loads of stuff.
there is a php-mssql module as well which might be handy.