java.lang.Throwable: Child Error

[Carmen Manzulli]

i've got this problem running my code for a simpleSelectComputation:

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

i don't know what does it mean but if it referes to mapred.child.java.opts
in which way  will i have to change this value?

who can help me?