I tried posting this at the buddypress forums, but I can't get in there. It tells me I ought to use my wordpress account, but then doens't allow me in.
Anyhow, I probably did something wrong in updating my multisite with buddypress to wp 3.1.
The most annoying problem is that the wp dbmanager plugin gives the following warning
'Your backup folder MIGHT be visible to the public
To correct this issue, move the .htaccess file from wp-content/plugins/wp-dbmanager to'
However, there is no htaccess file in that folder.
And unfortunately that warning shows up to scare of new people signing up for the site as well. :(