Can't login after upgrade

Hello All. I'm going to have to go out to the co-lo to investage further, but. I just updated a suse 9.0 box using You. It installed a new kernel amongst other things. I issued a reboot and the machine went down, and came up. One problem. Now when I go to ssh in, it asks for the password and refuses me. Wierd. Anyone come across something similar? A mangled /etc/passwd ? Dave.