Fixes problems that prevent installing or updating WordPress, themes, and plugins on some FTP server configurations (typically Pure-FTPd).
Some server configurations running Pure-FTPd have trouble updating WordPress via FTP. Common error messages when trying to update WordPress or update/install a plugin look like this:
Each of these cases seem to be related. There is a patch going into WordPress 3.2 that should take care of the issues and the plugin will be obsolete after updating to that version (http://core.trac.wordpress.org/ticket/10913). In the meantime, install and activate this plugin. Updates should work as expected.