Not able to enable LDAP on PHP 5.2.10 on 64 bit machine

Question

I am trying to enable the LDAP extension for PHP 5.2.10 on a 64 bit windows 2003 server. I have followed the mandatory steps:

1. Enabling the dll in php.ini
2. Checking extensions directory.
3. Ensuring that the dll is present in the extensions directory.
4. Restarted the web server.

However i have not been successful.

Any help on how to proceed will be highly appreciated.