Using NConf v1.3.0 with Icinga v1.7.1/Icinga-Web v1.7.2 on CentOS v6.3 32-bit.
PHP is version 5.3.3. MySQL is version 14.14.
I couldn't get Active Directory authentication to work out of the box, and looking through the forums and Google, looks like others were having trouble as well.
I rewrote the section in include/login_check.php that handles "ad_ldap" authentication. Working great for me with Windows Server 2003 Active Directory.
If anyone's interested, here's the rewritten section:
Here's sample config info for config/authentication.php: