”Sorry, the WP Super Cache admin page only works on the main site of this network.” (development version)

But it IS the main site. Clicking the link leads to a 404. It thinks it is a WPMU site rather than a 3.0.1 site.

Also, since adding custom menus in a child theme of Twenty Ten, a few new ”published” items have been added to the database. They are not really ”published”, just placeholders/aliases of some kind, with urls like /2010/08/25/2467/ which go nowhere. However, when Super Cache does its preload thing, it tries to access those placeholders, which leads to a bunch of 404:s.

A third complaint is that the preload mechanism stalls too easily. Maybe something with WP Cron, but nevertheless it is not reliable at all.