https://twitter.com/#!/kovshenin/status/180544972313985024
It’s important for a network (WordPress Multisite) to have a valid default theme for newly created sites. The current version sets this to twentyeleven in default-constants.php. If your default theme isn’t installed or disabled network-wide, you might face some errors when creating new sites in the network. You can define WP_DEFAULT_THEME in your wp-config.php file.
