Implementing NeHe Lesson 48 ArcBall Rotation

Hi i’m trying to get NeHe’s ArchBall rotation lesson 48 (which is here http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=48) working in Xith3D so i can use it in my current project, its seems to be almost wright, i was wondering if someone can have a look at the code, run it and see if they can see a problem to help us out please. I’ve pasted the code on sourcepost, here is the link http://sourcepost.sytes.net/sourceview.aspx?source_id=11734