From Liz, KLOW administrator:
WordPress 3.1.3 will be showing up as an available update — please don’t do it. It causes a problem that will keep you from uploading files to your site.  I will let you know when it is safe to update, or when I have a fix for the problem (if you have already updated).
I have a solution for the problem with the media library, but I will need to know that you have updated. If you have updated to 3.1.3, please contact me and I will apply the fix to your site.