NullPointerException in ShadowScalarType.java

Hello,

I recently came across the following exception:

java.lang.NullPointerException
  at visad.ShadowScalarType.<init>(ShadowScalarType.java:92)
  at visad.ShadowRealType.<init>(ShadowRealType.java:41)
  at visad.java3d.ShadowRealTypeJ3D.<init>(ShadowRealTypeJ3D.java:48)
  at visad.java3d.RendererJ3D.makeShadowRealType(RendererJ3D.java:130)
  at visad.RealType.buildShadowType(RealType.java:1096)
  at visad.java3d.ShadowRealTupleTypeJ3D.<init>(ShadowRealTupleTypeJ3D.java:48)
  at visad.java3d.RendererJ3D.makeShadowRealTupleType(RendererJ3D.java:124)
  at visad.RealTupleType.buildShadowType(RealTupleType.java:501)
  at visad.DataDisplayLink.prepareData(DataDisplayLink.java:258)
  at visad.DataRenderer.prepareAction(DataRenderer.java:314)
  at visad.DisplayRenderer.prepareAction(DisplayRenderer.java:745)
  at visad.DisplayImpl.doAction(DisplayImpl.java:1512)
  at visad.ActionImpl.run(ActionImpl.java:353)
  at visad.util.ThreadPool$ThreadMinnow.run(ThreadPool.java:95

with line 92 of ShadowScalarType.java being:
>        ValueIndices[map.getValueIndex()]++;


I'm unable to replicate the problem, but am wondering
if this is a timing issue whereby the "ValueIndices"
array is not ready yet.

Any ideas?

Thanks,
Jim.
---
Jim Koutsovasilis
Bureau of Meteorology, Australia
jimk@xxxxxxxxxx