FIX: "Access Denied" Error Loading Local XML File When ServerHTTPRequest Property Is True

To load an XML document from a server that is located behind a firewall, with the ServerHTTPRequest property set to True, you must first run the WinHTTP Proxy Configuration Utility (Proxycfg.exe). However, if the XML document is loaded from a server that is not behind a firewall, you should not need to first run Proxycfg.exe, even if you only use the proxycfg -d command.

Steps to Reproduce Behavior

To properly reproduce the error, use a system on which Proxycfg.exe has not been run.

1. Create the test XML document.
   1. Create a new text document by using Microsoft Notepad or another text editor.
   2. Paste the following code into the new text document:

         <?xml version="1.0"?>
         <bookstore>
              <book>
          <title>Where's Where in Charlotte</title>
            <author>Irina Vinzovskaia</author>
             </book>
         </bookstore>
      

   3. Save the text file as C:\INETPub\Wwwroot\Q291841.xml.
2. Create an Active Server Pages (ASP) page to load the XML document.
   1. Create a new text document by using Microsoft Notepad or another text editor.
   2. Paste the following code into the new text document:

         <%
         Set oXMLDoc = Server.CreateObject("MSXML2.DOMDocument.3.0")
         oXMLDoc.setProperty "ServerHTTPRequest", true
         oXMLDoc.async=False
      
         oXMLDoc.load "http://localhost/Q291841.xml"
      
         if oXMLDoc.parseError.reason <> "" then
             Response.Write "XML load failed: " & oXMLDoc.parseError.reason
         else
             Response.Write "XML load succeeded!"
         end if
         %>
      

   3. Save the file as C:\Inetpub\Wwwroot\Q291841.asp.
3. For testing purposes, in the Internet Services Manager, configure
   Application Protection of the virtual root to High (Isolated) (out of process) or Medium.
4. Browse to http://localhost/Q291841.asp.

The load fails with the error listed in the "Symptoms" section.