CentOS 5.8 - Can't login to tty1 as root after updates?

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http://serverfault.com – I've ran a yum update on my CentOS 5.8 box and now I am unable to log into the console as root. Basically what happens is I receive the login prompt, enter the correct username and password, and am immediately spit back to the login prompt. If I enter an incorrect password, I am told the password is incorrect, therefore I know that I am using the proper credentials. The only log I can seem to find of what's going on is /var/log/secure which simply contains: 15:33:41 centosbox login: pam_unix(login:session): session opened for user root by (uid=0) 15:33:41 centosbox login: ROOT LOGIN ON tty (HowTos)