To all those who are using WordPress Automatic Upgrade and may have upgraded to WordPress 2.5 there is a bug which was reported earlier which breaks automatic plugin updates which is a feature in WordPress 2.5.
This feature breaks because of a library we used to handle zip files which is also used by the plugin updater. Since the plugin updater does not need to check if the class in question has already been instantiated I have changed the code in the plugin to ensure that the PclZip library is not loaded while updating a plugin.
Anyway for those who do want to continue using WordPress Automatic Upgrade plugin please update to the latest version first or else if you are already using WordPress 2.5 first deactivate the plugin and then update and activate it.
I take immense pleasure in saying this too that WPAU has reached version 1.0 and actively supports upgrading from WordPress 2.5 to any new version that may be released.
Download: WordPress Automatic Upgrade v1.0