Automatic plugin upgrade for WordPress is a gem of a feature, when it works. If you’ve tried updating your WordPress plugins using “upgrade automatically” in the plugins list and are getting error messages like:
“Installation Failed” or “Cannot download update from http://downloads.wordpress.org/”
You might try going to your host and making sure CGI support is enabled. I’m not sure if this is a must for the automatic upgrade plugin feature in WordPress to actually work, however, enabling CGI worked for me when recently encountering these errors.
Naturally double check your FTP username and password are correct and relax the CHMOD permissions on /wp-content/upgrade folder.