After running the automated upgrade to 3.4, I receive the message
Fatal error: Call to undefined function get_option() in /.../wp-admin/admin.php on line 32
I have renamed plugins/ to plugins2/, renamed themes/ to themes2/, created themes/ and placed twentyten in there.
Still fails with same error.
I have downloaded a copy of 3.4, and uploaded /wp-admin and /wp-includes.
Still fails with the same error.
Why is WordPress so flaky with upgrades?