Undecodable data when reading URI at byte 0 ?

There is a strange issue that I do not understand. 

Trying to validate an RDF/XML file, and get the following reply

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

The RDF/XML file, if copied and pasted into the text box, validates all right. If the same URI is used by other RDF clients, like Tim's validator, of if it is simply dereferenced by, say, Firefox, it looks all right. Looking at the file with dump does not reveal any extra character at the beginning. Any hints?


Ivan


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Ivan Herman, W3C Semantic Web Activity Lead
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FOAF: http://www.ivan-herman.net/foaf.rdf