The same thing happened to me. My WordPress had a message to update, but there’s no updates do my language (pt-BR) so I updated to english but for my surprise, my WordPress comes to beta version 3.1.
I solved the problem, but it’s an alert. Some thing is wrong with new updates to new version in another language. (not the blog original language)
For annotation: I solved the problem deleting the core files and uploading the files of 3.0.3 version to my server.