Solution:
Apache
Open your apache directory and open httpd.conf then uncomment this LDAP Module so this module will be loaded when web server starts.
LoadModule ldap_module modules/mod_ldap.so
PHP
Open your PHP directory, and open file PHP.INI and enable PHP LDAP Extension.
extension=php_ldap.dll
Afterall, restart your web server, and check whether LDAP Module has been loaded.
To check, you can create New PHP File consisting this php block codes:
