Using AfxBeginThread in c++ with managed c++ and c#

I have a solution with a c# project, Managed c++ and Native c++.

I call a function in the native c++ which has

AfxBeginThread(
               Start_new_child_process,
               (LPVOID)Setting,
               NULL,
               0,
               0,
               NULL
               );

when I try calling the native c++ function from the C# project via the Managed c++ project i get this error:

Dubug Assertation failed!

Program: ...GUI.vshost.exe

File: f"dd\vctools\vc7libs\ship\atlmfc\afxwin1.inl

Line:21

Using the same code with only the C++ Native project works fine!
Any idea how to solve the problem?

thanks

Tags: C++ (C++/CLI), C#