java.lang.NullPointerException while upgrading to 3.1.1

2013-09-09 15:05:28,947 ERROR [IncrementalPinger1 ] fisheye CrossRepositoryRescanRequest-doRequest - Exception during cross-repository scan: 
java.lang.NullPointerException
	at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:187)
	at com.cenqua.fisheye.crossrepo.ChangesetDoc.fromChangeSet(ChangesetDoc.java:143)
	at com.cenqua.fisheye.csindex.ChangesetIndexer$5.apply(ChangesetIndexer.java:154)
	at com.cenqua.fisheye.csindex.ChangesetIndexer$5.apply(ChangesetIndexer.java:151)
	at com.cenqua.fisheye.csindex.ChangesetIndexer.writeInBatches(ChangesetIndexer.java:169)
	at com.cenqua.fisheye.csindex.ChangesetIndexer.indexChangesetsAndAuthors(ChangesetIndexer.java:151)
	at com.cenqua.fisheye.csindex.ChangesetIndexer.indexChangesetsAndAuthors(ChangesetIndexer.java:120)
	at com.atlassian.fisheye.svn.Svn2Scanner.indexChangeSets(Svn2Scanner.java:531)
	at com.atlassian.fisheye.svn.Svn2Scanner.reindexChangesets(Svn2Scanner.java:1042)
	at com.cenqua.fisheye.rep.ping.CrossRepositoryRescanRequest.doCrossRepoRescanCheck(CrossRepositoryRescanRequest.java:129)
	at com.cenqua.fisheye.rep.ping.CrossRepositoryRescanRequest.access$000(CrossRepositoryRescanRequest.java:30)
	at com.cenqua.fisheye.rep.ping.CrossRepositoryRescanRequest$1.apply(CrossRepositoryRescanRequest.java:60)
	at com.cenqua.fisheye.rep.ping.CrossRepositoryRescanRequest$1.apply(CrossRepositoryRescanRequest.java:57)
	at com.cenqua.fisheye.rep.RepositoryHandle.withEngine(RepositoryHandle.java:507)
	at com.cenqua.fisheye.rep.ping.CrossRepositoryRescanRequest.doRequest(CrossRepositoryRescanRequest.java:57)
	at com.cenqua.fisheye.rep.ping.PingRequest.process(PingRequest.java:51)
	at com.cenqua.fisheye.rep.RepositoryHandle.processPingRequests(RepositoryHandle.java:230)
	at com.cenqua.fisheye.rep.RepositoryHandle.access$100(RepositoryHandle.java:61)
	at com.cenqua.fisheye.rep.RepositoryHandle$2.run(RepositoryHandle.java:186)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
	at java.lang.Thread.run(Thread.java:636)