Kerberos keytab error when trying to join Kerberos…

Hello. I have one Xserve running as an OD Master, running 10.5.6 Server. I have a second Xserve, also running 10.5.6 Server set up with OD role "Connected to a Directory System" (with Directory System being the first Xserve). But, when, on the second Xserve, I try and "Join Kerberos..." and I fill in the following info: REALM: xserve001.domain.com Administrator Name: shortname of directory admin Password: password of directory admin When I click "OK", I get the following error: Kerberos keytab error Error while creating the Kerberos keytab file for this server. Does anyone know what I'm doing wrong? This second Xserve USED to be a replica of the OD Master, but it was demoted to Stand Alone, then set to "Connected to a Directory System" — could this have anything to do with the error? Thanks, Kristin.