Error: system identifier (URI) in the DOCTYPE

Could you help me understand this error message at
[http://jigsaw.w3.org/css-validator/validator?uri=http://nypl.org/branch/clickon/]?
I am following the "check it for validity" link from this valid document
at [http://validator.w3.org/check?uri=http://nypl.org/branch/clickon/].

Error
Target: http://nypl.org/branch/clickon/
org.xml.sax.SAXException: Please, fix your system identifier (URI) in
the DOCTYPE rule. 

The DOCTYPE used in this document is:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/tr/xhtml1/DTD/xhtml1-transitional.dtd">

Should I use something other than
"http://www.w3.org/tr/xhtml1/DTD/xhtml1-transitional.dtd"?

Thank you.

Kevin Sullivan
Internet Systems Manager
Mid-Continent Public Library
http://www.mcpl.lib.mo.us
mailto:web@mcpl.lib.mo.us

Received on Friday, 25 January 2002 11:19:36 UTC