Calling existing c++ functions from web service

[Denis]

Hello,

I am working on a large business application written mostly with VC++
and MFC. What I'm trying to do is accessing my database with the
existing functions in my c++ application using XML Web Services.

I decided to separate the function call from my Web Service. In order
to do this I create a project (unmanaged c++ as a static lib) where
all the functions to create a connection and request to my application
will be. Having VS.NET I used the Walkthrough: Creating an XML Web
Service Using Managed Extensions for C++ to create my Web Service.
That worked just fine. But when I compiled my Web Service (managed
c++) after including my previous project I received the following
errors:

c:\Program Files\Microsoft Visual Studio .NET
2003\Vc7\PlatformSDK\Include\ServProv.h(48) : warning C4935: assembly
access specifier modified from 'public'
c:\Program Files\Microsoft Visual Studio .NET
2003\Vc7\PlatformSDK\Include\ServProv.h(93) : error C2872:
'IServiceProvider' : ambiguous symbol
could be 'c:\Program Files\Microsoft Visual Studio .NET
2003\Vc7\PlatformSDK\Include\ServProv.h(48) : System::IServiceProvider
IServiceProvider'
or 'stdafx.cpp(0) : System::IServiceProvider'
c:\Program Files\Microsoft Visual Studio .NET
2003\Vc7\PlatformSDK\Include\ServProv.h(100) : fatal error C1903:
unable to recover from previous error(s); stopping compilation

This is without calling a single function from that project class in
my Web Service. Moreover compiling the unmanaged project alone works
fine. I hope I've been clear enough. What can I do to solve this
problem?

Denis