我试图从eclipse运行elasticmapreduce，但是做不到。
我的代码如下：

public class RunEMR {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         AWSCredentials credentials = new BasicAWSCredentials("xxxx","xxxx");
            AmazonElasticMapReduceClient emr = new AmazonElasticMapReduceClient(credentials);

            StepFactory stepFactory = new StepFactory();

            StepConfig enableDebugging = new StepConfig()
                .withName("Enable Debugging")
                .withActionOnFailure("TERMINATE_JOB_FLOW")
                .withHadoopJarStep(stepFactory.newEnableDebuggingStep());

            StepConfig installHive = new StepConfig()
                .withName("Install Hive")
                .withActionOnFailure("TERMINATE_JOB_FLOW")
                .withHadoopJarStep(stepFactory.newInstallHiveStep());

            StepConfig hiveScript = new StepConfig().withName("Hive Script")
                .withActionOnFailure("TERMINATE_JOB_FLOW")
                .withHadoopJarStep(stepFactory.newRunHiveScriptStep("s3://mywordcountbuckett/binary/WordCount.jar"));

            RunJobFlowRequest request = new RunJobFlowRequest()
                .withName("Hive Interactive")
                .withSteps(enableDebugging, installHive)
                .withLogUri("s3://mywordcountbuckett/")
                .withInstances(new JobFlowInstancesConfig()
                    .withEc2KeyName("xxxx")
                    .withHadoopVersion("0.20")
                    .withInstanceCount(3)
                    .withKeepJobFlowAliveWhenNoSteps(true)
                    .withMasterInstanceType("m1.small")
                    .withSlaveInstanceType("m1.small"));

            RunJobFlowResult result = emr.runJobFlow(request);

    }

}

我得到的错误是：

Exception in thread "main" com.amazonaws.AmazonServiceException: InstanceProfile is required for creating cluster. (Service: AmazonElasticMapReduce; Status Code: 400; Error Code: ValidationException; Request ID: 7a96ee32-9744-11e5-947d-65ca8f7db0a5

我试了几个小时，但没能修好。有人知道怎么做吗？