Thread:Extension talk:LDAP Authentication/LDAP auth works, but cannot get SSO to work

This problem has been driving me insane. (Note: all versions and settings are below) I have mediawiki setup with the LDAP Authentication plugin. I have it successfully authenticate against AD, it will filter by group without any trouble, and it will even import nickname, realname, and email addresses without any issues. I add the appropriate settings to turn on SSO (and take out the one line I don't need) and then all I get is HTTP 500 errors. I have gone through an unbelieveable amount of documentation on this and found nothing. Other plugins can do SSO, but they can't do the group based filtering that this one can. I need some help understanding what is going wrong.

OS: Windows Server 2008 R2 SP1

Webserver: IIS 7.5 (I have to use this; Apache is not an option.)

Mediawiki Version: 1.20.2

LDAP Authentication Version: 2.0c

PHP Version: 5.3.21

MySQL Version: 5.5

LDAP Directory: Active Directory on Server 2008 R2 running at Server 2003 Level

Web Site Authentication Settings:

Anonymous Authentication: Disabled

Basic Authentication: Enabled

Windows Authentication: Enabled

Here are the added lines to my localsettings.php:

This setup works perfectly. Here is what I changed to turn on SSO:

After that, it will only give me HTTP 500 errors; it will not display the website. Have no idea what to do. Any help would be appreciated. Thanks.