As we know ASP.NET AJAX allows us to invoke web services through what we call it AJAX network calls, when we add a reference to a web service to the page's Script Manager we instruct it to generate a proxy client for that web service in a JS format ,

for certain reason this is always a problem in MOSS, if you are having the same problem all you have to do as a work around is to generate a the proxy client manually and save it as part of the MOSS resources as a JS file and start linking this file in your pages instead of the service reference tag in the Script Manager

this works just fine but it has couple of problems such as you will need to update this proxy manually each time you change the web service signatures