When i use papervision in flash builder and i am doing a test, when i render a sphere using papervision with the following code it renders me the sphere.

When i add a line sphere.pitch(2); ||
i get the following error,

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at PvTest/onRenderTick()[D:\Android 3D\PvTest\src\PvTest.as:39]

Can anyone help me figure out the error
For additional Info, these are the imports i am doing:

import org.papervision3d.objects.primitives.Sphere;
import org.papervision3d.view.BasicView;