Loader.exe is a Win32 application that can load a .NET application after checking for the existence of the .NET Framework (specifically, MSCOREE.DLL). If MSCOREE.DLL is not found, the loader points the user to the Microsoft .NET Framework home page where they can download the .NET Framework.
The point behind all this is the avoidance of the "MSCOREE.DLL not found" error message when a user tries to execute a .NET application without the .NET Framework installed. The error message above is replaced with a much friendlier message, telling the user that they don't have the .NET Framework.
NetXP has one of the world's most comprehensive Win32 wrappers for .NET. It contains the declarations of some 1600 API functions. Using the pre-declared APIs in the NetXP Win32 wrapper is not only easier but also less error-prone. All of the APIs declared in the Win32 wrapper are guaranteed to be error-free.