Some wrong in DataFu Hourglass's Getting Started.

[Daniel Wang]

hi ,I did some test by following the
http://datafu.incubator.apache.org/docs/hourglass/getting-started.html,
but when I run " hadoop jar build/datafu-hourglass-test.jar countbyid
-libjars ${LIBJARS} /data/event /output" some wrong as:
14/03/15 12:11:32 INFO mapreduce.Job:  map 0% reduce 0%
14/03/15 12:11:48 INFO mapreduce.Job:  map 7% reduce 0%
14/03/15 12:11:48 INFO mapreduce.Job: Task Id :
attempt_1394813193657_0003_m_000011_0, Status : FAILED
Error: Found interface org.apache.hadoop.mapreduce.TaskAttemptContext,
but class was expected
14/03/15 12:11:48 INFO mapreduce.Job: Task Id :
attempt_1394813193657_0003_m_000010_0, Status : FAILED
Error: Found interface org.apache.hadoop.mapreduce.TaskAttemptContext,
but class was expected
14/03/15 12:11:49 INFO mapreduce.Job:  map 0% reduce 0%
14/03/15 12:11:49 INFO mapreduce.Job: Task Id :
attempt_1394813193657_0003_m_000009_0, Status : FAILED
...
14/03/15 12:12:52 ERROR
jobs.AbstractPartitionCollapsingIncrementalJob: Job failed!
Quitting...
14/03/15 12:12:52 INFO jobs.FileCleaner: Removing
/tmp/hourglass-97bfce22-d8f5-4422-a894-7fb15f5e3517
java.lang.RuntimeException: Job failed
        at 
datafu.hourglass.jobs.AbstractPartitionCollapsingIncrementalJob.execute(AbstractPartitionCollapsingIncrementalJob.java:544)
        at 
datafu.hourglass.jobs.AbstractPartitionCollapsingIncrementalJob.run(AbstractPartitionCollapsingIncrementalJob.java:352)
        at datafu.hourglass.demo.CountById.run(CountById.java:157)
        at datafu.hourglass.demo.CountById.run(CountById.java:60)
        at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
        at datafu.hourglass.demo.Main.run(Main.java:63)
        at datafu.hourglass.demo.Main.main(Main.java:48)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at 
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:622)
        at org.apache.hadoop.util.RunJar.main(RunJar.java:212)
Hourglass demo tool.

What is wrong with it? How to fix it? Thanks!