BuddyPress.org

First, always read the “readme.txt” file before proceeding with any WPMU or BuddyPress upgrade.

Before installing BuddyPress from trunk, you need to make sure that you are running WPMU 2.8.4a. If not, you need to deactivate all WPMU plugins, upgrade WPMU, and then try again. The latest WPMU version can be found here.

Once you’ve installed BuddyPress, make sure you move the theme files into their proper location.