Warning: The PHP LDAP module does not seem to be present. Please ensure it is installed and enabled.
This usually means that the main ldap dll or one of the supporting dlls are missing. Let's start with the main one itself. Browse to http://(moodleserver)/admin/phpinfo.php
and examine the "Configuration File (php.ini) Path" field to determine which php.ini is being used and open it with an editor. Find the line 'extension=php_ldap.dll' and take out the semi-colon if it is there. That semi-colon will stop it loading the module all together! While you have that file open, search for 'extension_dir' and note which folder it is set to. Open that folder and ensure the php_ldap.dll file is in there. If it isn't then put it in there. If that still hasn't fixed it you are missing a supporting dll, but you don't get told that. To see what dlls are missing open the Command Prompt and navigate to the php directory and execute the following line 'php -m'. You should get some error messages now. Ugly, but at least they give you information! Find the dlls listed and copy them to the php directory. You may now need to restart the apache/httpd service. Run 'php -m' again and you should be error free and the message in Moodle should be gone now.