升级到php 5.3.x后找不到PDO类致命错误

我们进行了服务器升级，将表格5.2.x移至php5.3.x.我是mysql pdo，代码如下所示，在升级之前可以正常工作.

We had a server upgrade where we moved form 5.2.x to php 5.3.x. I was mysql pdo with the code showen below which was working before the upgrade.

    <?php

error_reporting(E_ALL);
ini_set('display_errors', '1');


/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Database user / pass
 */
$sql_details = array(
    "user" => "",
    "pass" => "",
    "host" => "",
    "db" => ""
);


// This is included for the development and deploy environment used on the DataTables
// server. You can delete this block - it just includes my own user/pass without making 
// them public!
if ( is_file($_SERVER['DOCUMENT_ROOT']."/datatables/pdo.php") ) {
    include( $_SERVER['DOCUMENT_ROOT']."/datatables/pdo.php" );
}
// /End development include


/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Database connection
 */

/* PDO connection */
$db = new PDO(
    "mysql:host={$sql_details['host']};dbname={$sql_details['db']}",
    $sql_details['user'],
    $sql_details['pass'],
    array(
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
    )
);

/* mysql_* connection */
/*
if ( ! $db = mysql_pconnect( $sql_details['host'], $sql_details['user'], $sql_details['pass'] ) ) {
    header( $_SERVER['SERVER_PROTOCOL'] .' 500 Internal Server Error' );
    die( 'Could not open connection to server' );
}

if ( ! mysql_select_db( $sql_details['db'], $db ) ) {
    header( $_SERVER['SERVER_PROTOCOL'] .' 500 Internal Server Error' );
    die( 'Could not select database' );
}
*/

但是升级后，我收到一个致命错误，即找不到PDO类.我检查ht php.ini并启用了pdo.以下是php.ini中的代码段.

But after the upgrade, i get a fatal error that PDO class not found. I check ht php.ini and pdo is enabled. Below is the snippet from php.ini.

'--with-mysql=/usr' '--with-mysql-sock=/var/lib/mysql/mysql.sock' '--with-mysqli=/usr/bin/mysql_config' '--with-openssl=/usr' '--with-openssl-dir=/usr' '--with-pcre-regex=/opt/pcre' '--with-pdo-mysql=shared' '--with-pdo-sqlite=shared' '--with-pic' '--with-png-dir=/usr' '--with-sqlite=shared' '--with-xpm-dir=/usr' '--with-zlib' '--with-zlib-dir=/usr'
pdo_mysql
pdo_mysql.default_socket => /var/lib/mysql/mysql.sock => /var/lib/mysql/mysql.sock
pdo_sqlite

您能帮我解决这里的问题吗?

Could you please help me with whats the problem here?

预先感谢， 斯里尼.