Connect to Solid edge using C#

Question

Hi...
   I want to Connect to solid edge..I have write following code..

   SolidEdgeFramework.Application app = null;
   app = (SolidEdgeFramework.Application)Marshal.GetActiveObject("SolidEdge.Application");
    app.Visible = true;

       On 2nd line i get error "Operation unavailable (Exception from HRESULT: 0x800401E3 (MK_E_UNAVAILABLE)) "
   plz anyone tell me...Thanks