Method not found: 'Int64 Autodesk.AutoCAD.Interop.IAcadApplication.get_HWND()'.

Hello,

When I build my application in 32 bit windows, I got this error in 64 bit windows

System.MissingMethodException: Method not found: 'Int32 Autodesk.AutoCAD.Interop.IAcadApplication.get_HWND()'.

And when I build it in 64 bit windows, I got

System.MissingMethodException: Method not found: 'Int64 Autodesk.AutoCAD.Interop.IAcadApplication.get_HWND()'.

What can I do?

Thanks,