I apologize for taking so long to back with you on this. I had to find what I was looking for.
OK, you need to add a mapping for the .svc file. In IIS, right mouse click on the web site that isn't working, and select properties. On the Virtual Directory tab, click the Configuration button. That will bring up the Application Configuration screen. On the mappings tab, under the Appliction Extenstions, look to see if you have an entry for the .svc extension.
If you don't, you need to add one, and map it to the aspnet_isapi.dll.
To do this, simply click the Add button and browse to the isapi dll and enter an extension of .svc.
You should be good to go!
Let me know if I can help you with anything else.
Author - Professional SQL Server 2005 XML