I did a git pull in the cassandra dir and ran ant hoping things would run but cassandra does nt run

DEBUG - insert
ERROR - Internal error processing insert
java.lang.NullPointerException
        at org.apache.cassandra.service.ThriftValidation.validateColumnPath(ThriftValidation.java:61)
        at org.apache.cassandra.service.CassandraServer.insert(CassandraServer.java:262)
        at org.apache.cassandra.service.Cassandra$Processor$insert.process(Cassandra.java:927)
        at org.apache.cassandra.service.Cassandra$Processor.process(Cassandra.java:796)
        at org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:252)
        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)

is there a specific way to upgrade cassandra ie dump the db and restore?

thanks