Can't use an undefined value as an ARRAY reference at /usr/local/validator/httpd/cgi-bin/check line 2713

I try to validate a UTF-8 XML file that is apparently regarded as us-ascii. I suppose that should give me an error at the first non-ascii character.

What I get, looks more like a script error:
Can't use an undefined value as an ARRAY reference at /usr/local/validator/httpd/cgi-bin/check line 2713

The file is at http://heima.olivant.fo/~styrheim/xml/dataxml.aspx.xml, the validator link is http://validator.w3.org/check?uri=http%3A%2F%2Fheima.olivant.fo%2F~styrheim%2Fxml%2Fdataxml.aspx.xml+&charset=%28detect+automatically%29&doctype=Inline&group=0

If I tell the validator to use UTF-8, the file validates, but with warning of Missing "charset" attribute for "text/xml" document.

Jan Egil Kristiansen, KTF, Faroe Islands