Is not a valid win32 Application

  Recently I ran into a problem. I wanted to play around AudioVideoPlayback class. A FORM was good enough to deal with it. The solution built successfully. Then, BOMB, a message box popped up and said “xxx is not a valid win32 application. (Exception from HRESULT: 0x800700C1).” What a surprised!
  There was no luck from Google and MSDN. Most of the solution suggested to give up AudioVideoPlayback and used one project that was hosted in SourceForge. It was not the answer what I expected. Then an unrelated article has showed up in my eyes. The author was asked about a DLL that was managed code which call unmanaged code. It was built successful but cannot referenced and got an error: “is not a valid win32 application.” The repliers told about win32 application runs under 64-bit OS. Suddenly I thought I find the problem.
  The wizard generated the build solution with “Any CPU” option. It was Ok for a 32-bit Windows but 64-bit Windows. It seems this kind of the application will call 64-bit components at first in 64-bit Windows. Somehow AudioVideoPlayback had issue on 64-bit cross over to 32-bit. The issue would be gone if the build solution specified with x86 only.