Render crash with PhongColorMaterial at certain angles

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With the trunk FP10 build, I get a crash when Away3D renders a
scene that has many objects but only one  (a Cylinder primitive) that
has PhongColorMaterial applied.  It happens only at certain look
angles and camera distance/zoom settings and I
am having trouble forcing the crash under repeatable conditions.  It
does not happen with Away3D 3.4.0.  I am not using frustum clipping,
and the crash happens with or without RectangleClipping.

What steps will reproduce the problem?
1. Create a complex scene with numerous objects.  Apply PhongColorMaterial
to only one object.
2. Move camera around with mouse (hand-made version of HoverCam)
3. At certain angles, Away3D will fail to render.

What is the expected output? What do you see instead?
At certain view angles, Away3D crashes with messages such as this:

TypeError: Error #1009: Cannot access a property or method of a null
object reference.
        at away3d.materials.shaders::AbstractShader/getUVData()
        at away3d.materials.shaders::DiffusePhongShader/renderLayer()
        at away3d.materials::CompositeMaterial/renderLayer()
        at away3d.materials::CompositeMaterial/renderTriangle()
        at away3d.core.draw::DrawTriangle/render()
        at away3d.core.draw::PrimitiveQuadrantTreeNode/render()
        at away3d.core.draw::PrimitiveQuadrantTreeNode/render_other()
        at away3d.core.draw::PrimitiveQuadrantTreeNode/render()
        at away3d.core.draw::PrimitiveQuadrantTreeNode/render_other()
        at away3d.core.draw::PrimitiveQuadrantTreeNode/render()
        at away3d.core.draw::PrimitiveQuadrantTreeNode/render_other()
        at away3d.core.draw::PrimitiveQuadrantTreeNode/render()
        at away3d.core.render::QuadrantRenderer/render()
        at away3d.core.render::AbstractRenderSession/render()
        at away3d.core.render::AbstractRenderSession/render()
        at away3d.containers::View3D/render() 

What version of the product are you using? On what operating system?
Away3D FP10, trunk, SVN rev 2145.
Flash CS4.

Please provide any additional information below.
Problem does not occur with Away3D 3.4.0.

Original issue reported on code.google.com by ralph%sa...@gtempaccount.com on 13 Jan 2010 at 11:48

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Update: by trial and error, determined that problem starts with SVN trunk rev 
2137. 
If revert to rev 2131, problem does not occur.

Original comment by ralph%sa...@gtempaccount.com on 25 Jan 2010 at 2:50