/etc/nsswitch.conf: ... passwd: files ldap shadow: files ldap group: files ldap ... After check "files" exit UNAVAIL instead SUCCESS at login. After check "files" exit NOTFOUND instead SUCCESS at start mc.
My first suspicion would be nss_ldap module, because all other nss modules seem to work well.
Have you also enabled use of LDAP for authentication? Are the network interfaces up?
This happen if LDAP server not enabled. But login must be successful in any case if I am local user.
I think that this is a dup of bug# 63631 http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=63631 I think that your problem only occures when the ldap server is offline or unavalable.
This bug appear is absent in recent versions of RH. Bug #63631 is a dup of bug #26449. Please pay attention to it. In the bottom of #26449 problem is resolved by me.