BuddyPress.org

If you just care about your BP data, export all database tables with “wp_bp_” prefixed in them, as well as the “wp_users” and”wp_usermeta” tables.

Preferably try this on a new install of standard WP with BP installed on a local testbox.

Then try importing the tables you exported above into your testbox’s db.

Disclaimer: This is all theoretical!

There might be a few things you need to manually change in the SQL export, but I’m not sure at this point.

Also, hope you’re not using user blogs on WPMU!