Drivers are installed and configured correctly but PHP can still not find them

Hi,

I am trying to test my application on and IIS/MSSQL setup before trying to deploy it to a customer's site. I have a clean install of IIS, SQL Server and PHP. The Servers appear to be configured correctly. I have downloaded and installed drivers according to the Microsoft documentation. I have made sure the module is enabled in IIS and the entry isin the PHP.ini file.

Using "PHP -i" in powershell gives:

PHP Startup: Unable to load dynamic library

'C:\xampp\php\ext\php_pdo_sqlsrv_55_nts.dll' - The specified module could not be found.

I am using the PHP from my xampp installation as I need the newer version of PHP to support my application. The PHP version is 5.6.3.

When I try to connect to the database in PHP I get: 

#0 CACDB::fail(could not find driver) called at [C:\plato\dal\dbconn.php:24]

#1 CACDB->__construct() called at [C:\plato\dal\dbconn.php:36]

#2 CACDB::Connection() called at [C:\plato\dal\user.php:17] 

Thanks in advance,

Dion