I recently upgraded from 3.2.1 to 3.3.1 via Subversion using the command
svn sw http://core.svn.wordpress.org/tags/3.3.1/ .. I have been using a checkout from Subversion in such a fashion for quite some time.
After running this command, I cannot get to my dashboard, as visiting
wp-admin gives me a 'Page not found' error. I am unable to upgrade, as visiting
wp-admin/upgrade.php gives me a 'Page not found' error.
I tried downgrading to 3.2.1 using a similar
svn command, but that too gives me a 'Page not found' error for any page under
Before upgrading, I was able to get to my dashboard (this was how I found out there was a 3.3.1 upgrade in the first place).