I’ve seen this in a couple of places already, so I’ll go ahead an post it: If you’re getting an error with your WordPress install similar to: “Fatal error: Cannot redeclare pclziputilpathreduction()” and you’re using WP 2.7+, disable your WPAU – WordPress Automatic Upgrade plugin. This error is caused because in version 2.7 WordPress added the ability to update itself, so this plugin is no longer needed. Here is an image of what the deactivated plugin should look like on the plugins page:

Update: This appears to be fixed in the latest version of the plugin. I was able to enable the plugin and browse around without getting errors. But I don’t see the need for this plugin in WP installs newer than 2.6 anyway.