Error: Ambiguous reference error in Visual Studio .NET
When more than one ArcWeb Service is referenced in Visual Studio .NET, the following error may occur:
.NET returns an error if more than one Web service share the same object, even if that object is placed separately into every Web service namespace. For example, Geometry is an object shared between many ArcWeb services.
Solution or Workaround
Give a full namespace path when declaring the object.
For example, a declaration for a point object would be:
MyApplication is the name of your project
AddressFinder is the alias for the Web reference that points to the Address Finder Web Service WSDL.