AJP authentication fails with message "cannot authenticate user jstiefel because user's auth type 5 is not configured"

I'm using AJP authentication (AuthType basic) and it's failing to auth with the message:

2009-08-20 12:01:48,242 WARN [btpool0-28] fisheye.app com.cenqua.fisheye.user.UserManager-loginWithSanitizedUserName - cannot authenticate user jstiefel because user's auth type 5 is not configured

Can't find anything in the docs or google that is leading me anywhere on resolving this.

thanks!