I get an "Domain (null)/Error 0" error in iCal 3, when I try to use CalDAV with a domain other then our standard ldap domain. So, I use the host.com and everything works fine, when I use a username from this domain. But when I try to use user@host2.com I get this error. I have tried out everything, but didn't get it to work. The wiki entry is only helpful for the first situation.