I am not sure, but that problem may happen due an incompatibility between
the web service proxies generated in .NET 1.1 and the proxies generated in
VS automaticallty generates some code to consume the web services, if that
code was compiled using .NET 1.1 (Using some valid xml serialization rules
that are no longer valid in .NET 2.0), you will have problems to use the
same code in a .NET 2.0 application.