IndexWriter.optimize() throws NullPointerException

I am using lucene 2.3.2 search APIs for my application, i am indexing 45GB database which creates approax 200MB index file, after finishing the indexing and while running optimize() i can see NullPointerExcception thrown in my log and index file is getting corrupted, log says

------------------------------------------------------------------------
Caused by:
java.lang.NullPointerException
at org.apache.lucene.store.BufferedIndexOutput.writeBytes(BufferedIndexOutput.java:49)
at org.apache.lucene.store.IndexOutput.writeBytes(IndexOutput.java:40)
at org.apache.lucene.index.SegmentMerger.mergeNorms(SegmentMerger.java:566)
at org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:135)
at org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:3273)
at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:2968)
at org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:240)
------------------------------------------------------------------------
and this is happening quite frequently, although I am not able to reproduce it on demand, I saw an issue logged which is some what related to mine issue (http://mail-archives.apache.org/mod_mbox/lucene-solr-user/200809.mbox/%3C6E4A40DB-5EFC-42DA-A857-D59F4EC3496B@mikemccandless.com%3E) but the only difference here is I am not using Store.Compress for my fields, i am using Store.NO instead. please note that I am using IBM JRE for my application.

Is this an issue with lucene?, if yes it is fixed in which version?