So last night I went to upgrade this WordPress software to version 2.1. I used wget to get the latest.tar.gz from wordpress.org, and then I proceeded with the upgrade. Sadly, it did not work right away. I have done a number of upgrades and they all went very smoothly, so I was distressed. I googled around for the error message I was getting, “It doesn’t look like you’ve installed WP yet. Try running install.php.” It turns out this does happen sometimes and the typical problem is that the user_level of the admin user in table wp_users gets reset to 0, when in fact it should be 10. I entered the SQL commands manually to update this, and things once again worked. It was then that I realized what happened; I had just downgraded to version 1.5 by accident, because a latest.tar.gz already existed in my download directory. The new one was automatically named latest.tar.gz.1. Grr! Fortunately, I did make a backup before attempting the upgrade, so I restored version 2.0.5, and then did the upgrade to 2.1 without incident. Oops.