You need .Net 3.5 SP1 (service pack 1).
To re-install, do an uninstall from Programs and Settings and also delete the installation directory (e.g. C:\Program Files\Microsoft\Small Basic) before trying a re-install. Try reinstalling with a user that has admin privilidges.
If you do this and it still doen't work, you can test the SmallBasic dll is working with .Net by writing a simple C# VS2010 console project targetting .Net 3.5 (Solution Explorer->Properties->Application->Target framework->.NET Framework 3.5),
you can even add a reference to SmallBasicLibrary.dll (Project->Add Reference->Browse->C:\Program Files\Microsoft\Small Basic\SmallBasicLibrary.dll) and see if you can use this dll from VS. Note VS2010 uses .Net 4 by default.
For example:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SmallBasic.Library;
namespace TestSmallBasicLibrary
{
class Program
{
static void Main(string[] args)
{
GraphicsWindow.BackgroundColor = "Red";
}
}
}
Simple test C# VS2010 project uploaded
here .
