W3c HTML 4.01 checking links

Problem on my page
http://www.genuki.org.uk/big/wal/


Error message;
###################
Sorry! This document can not be checked.

    Error

    Sorry, this type of URL scheme ("undefined") is not supported by this 
service. Please check that you entered the URL correctly.

    URLs should be in the form: http://validator.w3.org/
##################


The link code used on all my pages , and have had for several years, is 
below.

href="http://validator.w3.org/check/referer"


I have almost 5000 such links, and there are many thousands more across 
Genuki, all worked fine up to last weekend.
I was hoping this was a temporary glitch at your end to avoid changing all 
these links - is it ?

Cheers


Gareth Hicks
Genuki maintainer
tirbach@clara.co.uk 

Received on Friday, 3 June 2011 11:36:47 UTC