I get errors trying to logon. For example:
[aaron@rodriguezhouse zcs]$ su prodriguez
Password:
su: incorrect password

in /var/log/messages it says

[root@localhost examples]# tail -f /var/log/messages
Jun 20 21:48:26 133-1 su: pam_ldap: ldap_simple_bind Can't contact LDAP server
Jun 20 21:48:26 133-1 pam_winbind[30543]: write to socket failed!
Jun 20 21:48:26 133-1 pam_winbind[30543]: internal module error (retval = 3, user = `prodriguez')

Im afraid to log off root until this is resolved.

Heres some more in the messages log
Jun 20 21:50:01 133-1 pam_winbind[30775]: write to socket failed!
Jun 20 21:50:01 133-1 pam_winbind[30775]: internal module error (retval = 3, user = `zimbra')
Jun 20 21:50:01 133-1 crond[30775]: Authentication service cannot retrieve authentication info
Jun 20 21:50:01 133-1 crond[30775]: CRON (zimbra) ERROR: failed to open PAM security session: Success
Jun 20 21:50:01 133-1 crond[30775]: CRON (zimbra) ERROR: cannot set security context
Jun 20 21:50:01 133-1 pam_winbind[30778]: write to socket failed!
Jun 20 21:50:01 133-1 pam_winbind[30776]: write to socket failed!
Jun 20 21:50:01 133-1 pam_winbind[30778]: internal module error (retval = 3, user = `zimbra')
Jun 20 21:50:01 133-1 pam_winbind[30776]: internal module error (retval = 3, user = `zimbra')
Jun 20 21:50:01 133-1 crond[30778]: Authentication service cannot retrieve authentication info
Jun 20 21:50:01 133-1 crond[30776]: Authentication service cannot retrieve authentication info
Jun 20 21:50:01 133-1 crond[30778]: CRON (zimbra) ERROR: failed to open PAM security session: Success
Jun 20 21:50:01 133-1 crond[30776]: CRON (zimbra) ERROR: failed to open PAM security session: Success
Jun 20 21:50:01 133-1 pam_winbind[30777]: write to socket failed!
Jun 20 21:50:01 133-1 crond[30778]: CRON (zimbra) ERROR: cannot set security context
Jun 20 21:50:01 133-1 crond[30776]: CRON (zimbra) ERROR: cannot set security context
Jun 20 21:50:01 133-1 pam_winbind[30777]: internal module error (retval = 3, user = `zimbra')
Jun 20 21:50:01 133-1 crond[30777]: Authentication service cannot retrieve authentication info
Jun 20 21:50:01 133-1 crond[30777]: CRON (zimbra) ERROR: failed to open PAM security session: Success
Jun 20 21:50:01 133-1 crond[30777]: CRON (zimbra) ERROR: cannot set security context