Does anyone know what these errors mean in console?

Question

This is the log from console.  In particular the parts "server not found in database"  and "failed building TGS-REP to...."  It only does this for the 10.8 clients not the 10.6 ones.  The users can log in, but if takes 30 computers about 10+ minutes to login.  Thanks.

Answer 1

That's the Kerberos Ticket Granting Server request and an Authentication Server request, among other chatter. 
Kerberos is a key part (no pun intended) of distributed authentication.
To verify one of the key low-level details — DNS and network services — that can cause issues for OS X Server including delayed network responses and generally flaky behavior, launch Terminal.app from Applications > Utilities and issue the following harmless, diagnostic command:
sudo changeip -checkhostname
You'll need to enter an administrative password for the sudo, and you might see a one-time informational message about the use of sudo, then some configuration information, and and indication of whether no changes are required, or of there are DNS or network issues.  Also confirm that the server is not using a .local name as its local DNS host name.
FWIW, here are some details of the Kerberos Protocol