RT::Authen::ExternalAuth problem with AD

I’ve gotten the extension installed, and have modified my RT_SiteConfig.pm correctly (or as best as I can figure based off the example configuration…), however, I cannot login with my personal AD credentials. The info I’m getting from logging follows:

[Thu Dec 18 01:32:57 2008] [warning]: Transaction->Create couldn’t, as you didn’t specify an object type and id (/usr/lib/perl5/vendor_perl/5.8.8/RT/Record.pm:1439)
[Thu Dec 18 01:32:57 2008] [error]: Couldn’t get principal for not loaded object (/usr/lib/perl5/vendor_perl/5.8.8/RT/User_Overlay.pm:1113)

Anyone else ran into this? If so, can you point me in the right direction to getting this fixed? Thanks.