After the automatic upgrade failed, I tried to execute a manual update. That failed and resulted in an “Error 500″ problem on the admin pages. I spent a couple of hours trying to figure out what happened and how to fix it. Basically, I was able to fix it by clearing out wp-config.php and rebuilding it from wp-config-sample.php. I used “wp-admin/setup-config.php" to effect the rebuild after I renamed the broken config file. I saved the old config file by renaming it wp-config-old.php with my FTP client (FileZilla). I edited the config file on my laptop with Adobe Dreamweaver, but any text editor should do.
I wrote this post after the fix, and also serves to test my posting ability.
Edit: One thing I forgot to mention is that I also had to disable and delete the security scan plug-in I had. I think it was called WP-SecurityScan. If you don’t disable it, you will get the “Error 500″ problem again. I am hosted on a 1and1 linux based package.