I have had moodle running for some time find on windows 2008 R2 SP 1 with apache 2.2 and mysql.
We use the apache sspi module with the .htaccess method from moodle.org

Recently we've been getting errors like:

[Tue Sep 20 18:08:31 2011] [crit] [client 178.103.60.247] configuration error: couldn't perform authentication. AuthType not set!: /

This is causing a lot of cpu activity and very slow log ons

The authname and authtype are set in the .htaccess file and liuke I say it has been working

any ideas please. If I can't solve it early tomoorw then i'm going to have to trun of single sign in, which isn't going to make me any friends