Moving a selected object in 3D space.

I have created a nurbs curve with it’s
control points. I can select the control points and move them with the mouse.

My problem is that the movement of the
control points will not match the
movement of the mouse.

Currently I am using gluUnProject to
determine how to move the control points.

How can I get the control points movement
to match the mouse movement.

Thanks

etharmon