title: (null) entry in command string exception in saveAsTextFile() on Pyspark
body: <p>I am working in PySpark on a Jupyter notebook (Python 2.7) in windows 7. I have an RDD of type <code>pyspark.rdd.PipelinedRDD</code> called <code>idSums</code>. When attempting to execute <code>idSums.saveAsTextFile("Output")</code>, I receive the following error:</p>
  
  <pre><code>Py4JJavaError: An error occurred while calling o834.saveAsTextFile.
  : org.apache.spark.SparkException: Job aborted due to stage failure: Task 1 in stage 33.0 failed 1 times, most recent failure: Lost task 1.0 in stage 33.0 (TID 131, localhost): java.io.IOException: (null) entry in command string: null chmod 0644 C:\Users\seride\Desktop\Experiments\PySpark\Output\_temporary\0\_temporary\attempt_201611231307_0033_m_000001_131\part-00001
  </code></pre>
  
  <p>There shouldn't be any problem with the RDD object, in my opinion, because I'm able to execute other actions without error, e.g. executing <code>idSums.collect()</code> produces the correct output.</p>
  
  <p>Furthermore, the <code>Output</code> directory is created (with all subdirectories) and the file <code>part-00001</code> is created, but it is 0 bytes.</p>