I installed the new wordpress 3.1, but it gave me some problems and I had restore everything, you'd know it help me? Practically after updating the site was completely white and I could not access the dashboard. I do not know if it's in conflict with some plugin or theme ... but I do not risk coming back to update: ( Can you help me? www.talkischeap.it
I had the same issue after upgrading my local environment (wordpress/xamp). I ran http://localhost/wordpress/wp-admin/upgrade.php and then I could get back in to the admin. I then had to update the database and upgrade to 3.1 again. After that all seems to be fine.
Hope it helps you too!