selinux-policy-targeted-1.17.30-2.90 troubles. (FC3)

[Omri Schwarz]

A machine installed as FC3 got its update from up2date yesterday
and now will no longer allow logins on the console, nor the X console, 
and will no longer allow the sudoers to sudo. 

Touching /.autorelabel and rebooting has not fixed the problem.

The sudo problem only leaves this message to the console:

root:system_r:unconfined_t is not a valid context

And this in the logs:

Mar 29 18:19:55 HOST sudo:     omri : TTY=pts/0 ; PWD=/nfs/newline/h1/omri ; 
USER=root ; COMMAND=/bin/su root

The attempt to log to the X console leaves this in the logs:

Mar 29 18:36:22 HOST gdm-binary[5538]: pam_krb5[5538]: authentication succeeds
for 'omri' (omri at KRB5REALM)
Mar 29 18:36:22 HOST gdm(pam_unix)[5538]: session opened for user omri by 
(uid=0)
Mar 29 18:36:22 HOST gdm[5135]: gdm_cleanup_children: child 5538 crashed of 
signal 6
Mar 29 18:36:22 HOST gdm[5135]: gdm_cleanup_children: Slave crashed, killing 
its children

Logging in as root leaves what might be slightly more useful:

Mar 29 18:43:56 HOST gdm(pam_unix)[6206]: session opened for user root by 
(uid=0)
Mar 29 18:43:56 HOST dbus-daemon-1: avc:  could not determine enforcing mode

Meanwhile, I can SSH in and su to root without a problem.

I am very much an SELinux newbie, and was hoping to learn about this system by 
installing the targeted policy and seeing it in action, but here I am 
mystified.
None of the messages are enough for me to figure out what needs chcon'ing.

So I would be much obliged for any help you could offer.