我正在运行一个map reduce程序，它在我的cdh quickstart vm上工作正常，但在尝试多节点集群时，它会出现以下错误：
WARN mapred.JobClient: Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same.
14/02/12 00:23:06 WARN mapred.JobClient: No job jar file set. User classes may not be found. See JobConf(Class) or JobConf#setJar(String).
14/02/12 00:23:06 INFO input.FileInputFormat: Total input paths to process : 1
14/02/12 00:23:07 INFO mapred.JobClient: Running job: job_201401221117_5777
14/02/12 00:23:08 INFO mapred.JobClient: map 0% reduce 0%
14/02/12 00:23:16 INFO mapred.JobClient: Task Id : attempt_201401221117_5777_m_000000_0, Status : FAILED
java.lang.RuntimeException: java.lang.ClassNotFoundException: Class Mappercsv not found
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1774)
at org.apache.hadoop.mapreduce.task.JobContextImpl.getMapperClass(JobContextImpl.java:191)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:631)
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)
Caused by: java.lang.ClassNotFoundException: Class Mappercsv not found
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:1680)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1772)
... 8 more"
请帮忙。