I uploaded one that I wrote some time ago that you can try. It is called the d20DiceRoller, but it will roll any type of die you want and in any combination. It will work best for a d20 game, but you could use it for others. What it doesn't do is automatically is count successes. Check it out though, it might work for what you are looking for.
It's uploaded here:
It does require .NET 1.1, but most Windows XP machines or better have at least that version. Hope that helps.