I’m getting the same error message when I tried to save General Settings after upgrading from version 1.31.3 to 2.0.7 on my test server running WordPress 3.9.
Looking in the code that error may mean it couldn’t contact the server to check the registration key?
It appears to be trying to contact:
which does not respond on port 80. Until that is working I cannot configure this version so I am going to revert back to version 1.31.3 for now.