In case you haven’t found a solution yet, check out: [http://core.trac.wordpress.org/ticket/14026]. This is going to be fixed in version 3.0.1. You can download this file [http://core.trac.wordpress.org/browser/branches/3.0/wp-admin/export.php] and put it in your /wp-admin directory. This fix worked for me.
I upgraded my WP site last night and now want to export from the server so I have a local copy. I’m having the similar error messages.
