Online instance validation - just not working

Hi, I have tried to use the online schema validator

  http://www.w3.org/2001/03/webdata/xsv

I am trying to validate an instance document.  In the "Address(es):"
input area, I have entered two URLs, separated by a space:

  http://sirius-software.com:9204/resources/schtst01.xml
  http://sirius-software.com:9204/resources/schtst01.xsd

When my web server is running (as it is right now), a GET to
these addresses returns an instance and schema document,
respectively.  However, when I click on "Get results" in this
section of your form, I get a blank page (I'm using Mozilla
Firefox as the browser).

I'm sure there's something very simple which I'm doing wrong.
If there are any tips you can give me, I would appreciate it.

Dave Evans, Sirius Software Inc., Cambridge MA USA
617-876-6677 ext. 204