WordPress MU

In
function get_blogs_of_user( $id, $all = false ) {

preg_match('/wp_(\d+)_capabilities/', $key, $match);

totally breaks every wpmu which doesn't have wp_ as the DB prefix.

Replace with

preg_match('/'.$wpmuBaseTablePrefix.'(\d+)_capabilities/', $key, $match);

http://trac.mu.wordpress.org/

Add a ticket, please.