我在Ubuntu12.04 lts服务器上运行3节点群集，并在其上安装了hadoop 1.2.1和JDK1.7，现在首先检查map reduce作业是否正在执行，我从hadoop-examples-1.2.1.jar执行了wordcount，得到了惊人的错误：

14/02/20 20:26:52 INFO mapred.JobClient: Running job: job_201402202023_0002
14/02/20 20:26:53 INFO mapred.JobClient:  map 0% reduce 0%
14/02/20 20:26:57 INFO mapred.JobClient: Task Id :attempt_201402202023_0002_m_000005_0, Status : FAILED
java.lang.Throwable: Child Error
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Task process exit with nonzero status of 1.
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:258)
attempt_201402202023_0002_m_000005_0: execvp: Permission denied
14/02/20 20:27:00 INFO mapred.JobClient: Task Id : attempt_201402202023_0002_r_000001_0, Status : FAILED
java.lang.Throwable: Child Error
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Task process exit with nonzero status of 1.
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:258)
attempt_201402202023_0002_r_000001_0: execvp: Permission denied
14/02/20 20:27:04 INFO mapred.JobClient: Task Id : attempt_201402202023_0002_m_000005_1, Status : FAILED
java.lang.Throwable: Child Error
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Task process exit with nonzero status of 1.
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:258)
attempt_201402202023_0002_m_000005_1: execvp: Permission denied
14/02/20 20:27:07 INFO mapred.JobClient: Task Id : attempt_201402202023_0002_r_000001_1, Status : FAILED
java.lang.Throwable: Child Error
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Task process exit with nonzero status of 1.
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:258)
attempt_201402202023_0002_r_000001_1: execvp: Permission denied
14/02/20 20:27:12 INFO mapred.JobClient: Task Id : attempt_201402202023_0002_m_000005_2, Status : FAILED
java.lang.Throwable: Child Error
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Task process exit with nonzero status of 1.
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:258)

在得到这个错误之后，我从SQLServer2008R2执行了sqoop导入，在这里我得到了相同的错误。我的作业日志文件也有相同的错误。我还通过webui验证了集群的堆大小是200mb。所以，对我来说，内存似乎没有问题，用户日志也有hadoop.temp.dir（/var/lib/hadoop）和stderr日志文件：

execvp: Permission denied

请让我知道我应该做什么来解决这个问题。