SharePoint : Issue creating Disco

I've followed the instructions to the letter, when I run disco.exe I get this error:

The HTML document does not contain web service discovery information.

Any suggestions?

http://msdn.microsoft.com/en-us/library/ms464040.aspx

From stackoverflow JL

• I had some problems with the declaration:

  <% @ WebService Language="C#" Class="MOSS_WebServices.My_Services, MOSS_WebServices ,  
  
  Version=1.0.0.0, Culture=neutral, PublicKeyToken=1b40cb3309a7591b" %>
  

  From JL