我是hadoop新手。我已经在vmware workstation上的linux mint中安装了hadoop-1.2.1，当我尝试在hadoop中运行示例jar时，它会显示以下错误：

hduser@linux-mint ~/hadoop $ hadoop jar hadoop-examples-1.2.1.jar  pi 3 10

Number of Maps  = 3
Samples per Map = 10
14/09/05 17:40:19 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

14/09/05 17:40:20 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 1 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

14/09/05 17:40:21 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 2 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

14/09/05 17:40:22 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 3 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

14/09/05 17:40:23 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 4 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

14/09/05 17:40:24 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 5 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

14/09/05 17:40:25 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 6 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

14/09/05 17:40:26 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 7 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

14/09/05 17:40:27 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 8 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

14/09/05 17:40:28 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:54310. Already tried 9 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

java.lang.RuntimeException: java.net.ConnectException: Call to localhost/127.0.0.1:54310 failed on connection exception: java.net.ConnectException: Connection refused
    at org.apache.hadoop.mapred.JobConf.getWorkingDirectory(JobConf.java:567)
    at org.apache.hadoop.mapred.FileInputFormat.setInputPaths(FileInputFormat.java:318)
    at org.apache.hadoop.examples.PiEstimator.estimate(PiEstimator.java:265)
    at org.apache.hadoop.examples.PiEstimator.run(PiEstimator.java:342)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
    at org.apache.hadoop.examples.PiEstimator.main(PiEstimator.java:351)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)
    at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:139)
    at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:64)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:160)

我的jps提供以下输出：

3792 SecondaryNameNode

4001 Task Tracker

3865 Job Tracker

3678 Data Node

3581 Name Node

4045 Jps

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