The complete message is:
Error 401.3 Access Denied
You are not authorized to view this page.
This behavior will occur if the SQLXML ISAPI extension DLL is not enabled in IIS.
To workaround this behavior:
01. Start / Administrative Tools / Internet Information Services (IIS) Manager.
02. Select <ServerName> (local computer), right-click Web Service Extension, and press Add a new Web service extension.
03. Type SQLxml into the Extension name box and press Add.
04. Navigate to \Program Files\Common Files\System\Ole DB\sqlisapi.dll in the Required files box.
05. Select the Set extension status to Allowed check box.
06. Press OK.
07. Start / Run / services.msc / OK.
08. Right-click IIS Admin Service and press Stop.
09. After the service stops, right-click IIS Admin Service and press Start.
10. Start / Administrative Tools / Internet Information Services (IIS) Manager.
11. Right-click Web Sites and press Properties.
12. Select the Services tab.
13. Select the Run WWW service in IIS 5.0 isolation mode box and press OK.