报错：Call to undefined function sqlsrv_connect()
system: Windows NT AY130517141027Z 6.1 build 7601 (Windows Server 2008 R2 Standard Edition Service Pack 1) AMD64
php 版本：5.3.13
thikphp版本: 3.0
PHP Extension Build API20090626,TS,VC9
我使用的驱动是：extension=php_sqlsrv_53_ts_vc9.dll
extension=php_pdo_sqlsrv_53_ts_vc9.dll
服务器已装：Microsoft SQL Server 2008 R2 Native Client
Microsoft SQL Server 2012 Native Client
依然报这个问题，求大神？