Since I upgraded to WP 3.1 I've had some weirdness happening on my main website that needs to be fixed as soon as possible. http://anglotopia.net
Some of my custom post types stopped working. If you try to go to the page you get a 404 error. If you try to go edit a custom post type - you can't edit it - the only option is to view.
It gets stranger when I add a new one and it works fine. I very much need the old posts to work - I have thousands of posts in custom post types and I can't manually re-add them all.
Here's a list of what I've tried already:
Flushed permalinks repeatedly
Deactivated all plugins
Switched to default theme
Checked all settings using Custom Post UI
I've also done a combination of these things over and over and nothing seems to get the posts I've already entered working again.