Can't write AverageBuilder result from command line?

Legacy User

I can use IOObjectWriter and ResultWriter to write the results of an AverageBuilder to a file when I run the setup from the GUI. But when I run it from the command line, it fails with:

G Apr 28, 2009 10:24:09 AM: [Fatal] NullPointerException occured in 1st application of IOObjectWriter (IOObjectWriter)
G Apr 28, 2009 10:24:09 AM: [Fatal] Process failed: operator cannot be executed. Check the log messages...

The rest of the file works fine; just the IOObjectWriter or ResultWriter fails.

How do you write the results of an AverageBuilder to a file from the command line?

Here's the XML of the operators:

      <operator name="AverageBuilder" class="AverageBuilder">
      </operator>
      <operator name="IOObjectWriter" class="IOObjectWriter">
          <parameter key="object_file"	value="training_perf_%{t}.txt"/>
          <parameter key="io_object"	value="AverageVector"/>
          <parameter key="output_type"	value="XML"/>
      </operator>

I

Legacy User

Looks like a bug in Operator.java, getParameterAsFile():

lines 1123--

					File parent = result.getParentFile();
					parent.mkdirs();

What if getParentFile() returns null?

Sure enough, if I change my ResultWriter result_file to 'results/training_res_%{t}.txt', it works.

Where do I file a bug report?