The .NET 3.0 Framework is only WCF, WF, WPF and CardSpace, everything
else is still .NET 2.0. In fact all of the .NET 3.0 components run on
the 2.0 CLR. So in short, you need to have .NET 2.0 installed in
order to run .NET 3.0 executables. In fact the system requirements
for .NET 3.0 ensure that you have the .NET 2.0 framework already
installed.