NoSuchElementException in Sqoop Merge

I use sqoop import to load initial full snapshot and daily incremental data. Once the data is in HDFS, I merge them with sqoop merge to get daily snapshot. Merge works fine for 12 of 17 DB2 tables. And I got the similar exception for the rest:
13/09/09 10:59:50 INFO mapred.JobClient: Task Id : attempt_201308211622_0171_m_000033_0, Status : FAILED
java.util.NoSuchElementException
at java.util.AbstractList$Itr.next(AbstractList.java:350)
at ORDERITEMS.__loadFromFields(ORDERITEMS.java:1916)
at ORDERITEMS.parse(ORDERITEMS.java:1735)
at org.apache.sqoop.mapreduce.MergeTextMapper.map(MergeTextMapper.java:53)
at org.apache.sqoop.mapreduce.MergeTextMapper.map(MergeTextMapper.java:34)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:140)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:672)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:330)
at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1408)
at org.apache.hadoop.mapred.Child.main(Child.java:262)

Is this a bug for merge tool? It seems to be data related since not all table merges fail. All data are imported by sqoop import tool. Thanks.