I am getting an exception when I run Hadoop with Cassandra that follows:

WARN org.apache.hadoop.mapred.Child (main): Error running child
java.lang.RuntimeException: InvalidRequestException(why:Start key's token sorts after end token)
at org.apache.cassandra.hadoop.ColumnFamilyRecordReader$WideRowIterator.maybeInit(ColumnFamilyRecordReader.java:453)

I don't know what exactly this message means and how to solve the problem ... I am using Priam for manager my cluster in Cassandra over Elastic Map/Reduce on Amazon ... 

Any hint helps ...