upgrading to wp 3.1.1 problem

Your upgrade did not complete successfully.

Try:
– switching to the Twenty Ten theme by renaming your current theme’s folder in wp-content/themes using FTP or whatever file management application your host provides.

– resetting the plugins folder by FTP or phpMyAdmin.

– re-uploading all files & folders – except the wp-content folder – from a fresh download of WordPress.

– re-running the upgrade manually using wp-admin/upgrade.php.