Just recently upgraded the site to WordPress 2.6, using the Automatic Upgrade plugin. It went well, until the very last step when it couldn’t log me back into the web site. Shutting down and restarting the web browser seemed to fix that. Next time I went to log into the administrative site, some funky PHP errors appeared that appeared to be caused by blank lines at the ends of the PHP files provided by the Automatic Upgrade feature. I edited the files, removed the last (blank) line, restarted the web server and all is well. Stay tuned.