When you run your .NET project then you might run into an error “Unable to load DLL ‘librfc32.dll’: The specified module could not be found. (Exception from HRESULT: 0x8007007E)”.
You are start to search for librfc32.dll download. Do not do that, you will waste a load of your time. Download SAP GUI for Windows here http://sapdocs.info/sap/sap-gui/download-sap-gui-7-3-and-patches-for-free/ and install then the error will be gone.