Dirk,

> What is the different between
>
> System Software Requirements => .NET Framework is Installed

"The Requirements Visualizer allows you to specify certain machine
environments that your application requires in order to run properly. If
these system requirements are not met, the installation will exit."

> and
>
> Core PreRequisites => .NET Framework 4.0 Redistributable Package ?

The Core PreRequisites feature in SetupBuilder makes it possible to
streamline the installation process and to ensure the pre-requisite
components are in place.

In other words, you can use the "Core PreRequisites" feature to install the
runtime (based on a pre-defined include script).

HTH,
Friedrich