rdf validator Check-by-URI broken

When I try to Check By URI, the RDF Validation Service gives an error.
For instance, on 

    http://www.w3.org/1999/02/22-rdf-syntax-ns

It says:

   RDF Load Error

   An attempt to load the RDF from URI
   'http://www.w3.org/1999/02/22-rdf-syntax-ns' failed. (Undecodable
   data when reading URI at byte 0 using encoding 'UTF-8'. Please check
   encoding and encoding declaration of your document.)  

I'm pretty sure that document is actually being served properly (as are
the others I've tried.)

        -- Sandro