siggi_holm on "Facebook Timeline. invalid because the given value 'is_is'"

Ok I have tried doing the following:

1) Disable all plugins except the Facebook plugin. Results: Get the same error as before.

2) Changing to the default Wordpress Theme. Results: Get the same error as before.

I am totally lost. How can I fix this error: Error: {"message":"Object at URL 'http://skodun.is/2012/09/09/testing-2/' of type 'article' is invalid because the given value 'is_is' for property 'og:locale:locale' could not be parsed as type 'enum'.","type":"Exception"}