[Plugin: WordPress MU Sitewide Tags Pages] Failed Install corrupted WPMU

So I install the plugin and activate it. Go to Admin->Options, check enable, update options. Then the site returns with 404 page not found. Now if I reload the wp-admin page, logged in as the site admin, I’ve lost my site admin menu and ability to admin other blogs. Its as if the the privs of my admin user to the site have been revoked, and the admin has been turned into a regular blog owner/editor. The only way to undo this is to do a complete wipeout and DB and webroot restore. Ideas? I’d like to be able to use global tags for my install.

http://wordpress.org/extend/plugins/wordpress-mu-sitewide-tags/