BatchedIndexDataLoader abruptly terminated when indexing

2011-11-02 18:22:26,443 ERROR [proj.zoie.impl.indexing.IndexingThread] - proj.zoie.impl.indexing.internal.BatchedIndexDataLoader@41616dd6 is abruptly terminated
java.lang.NullPointerException
at proj.zoie.impl.indexing.internal.BatchedIndexDataLoader.processBatch(BatchedIndexDataLoader.java:353)
at proj.zoie.impl.indexing.internal.BatchedIndexDataLoader$LoaderThread.run(BatchedIndexDataLoader.java:380)

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this error occured two times when indexing