Problem with Xerxces and IIS with anonymous user logins disabled?

["Laub, James" <ja...@documentum.com>]

We've developed a JSP application using the Xerces parser.  Our current
setup involves an IIS webserver proxying to an appserver.

We've been able to pin down what looks to be a problem between IIS with
disabled anonymous user logins and the Xerces parser.  The running theory is
that, apparently Xerces is unable to create the necessary header
information/credentials to allow authentication.  While the anonymous user
is enabled, this isn't a problem.  However, when the anonymous user login is
disabled, IIS challenges Xerces' request for the XML file and when the
authentication is rejected, the IIS log receives a 401 error while the
browser catches some (often misleading, e.g. general server 500 error)
variant of a  ~/<file>.xml error.