If you are running suse 9.0 AND kernel 2.6.x, you should have updated the kernel manually, cause 9.0 runs 2.4.x series by default. Updating the kernel can be troublesome, sometimes. I always prefer to wait for the distro to upgrade.
Anyway, try to create a new user and login to it. If you can shutdown as new user cleanly, the problem is inside some of your .files from your /home.