I'm getting a maddeningly generic error from the DataExtract widget in FlexViewer 3.7. It reads: "Problem. Unable to complete operation."

I created the viewer with the 3.7 version of ArcGIS Viewer for Flex, the "application builder".
The DataExtract widget is designed to work by calling a Clip and Ship geoprocessing service. I've set up such a service following the tutorial. As required, it is published as Asynchronous and exposes the three required named parameters.
- Area_of_Interest
- Layers_to_Clip
- Feature_Format
My service runs successfully when I call it in any way except from the DataExtract widget. The selected layers are successfully clipped using the submitted geometry, zipped, and placed in the arcgisserver/directories/arcgisjobs/../ directory. I can look at the output.zip file and it is successfully created in the jobs folder.
Even when I run the service through the widget it succeeds in creating the output .zip file. The error comes when it tries to access that location and offer the file for download.I never can seem to get it to the point of prompting the user to download.
This seems to be a different issue than the one described here or here where the .zip file is not being created.
I have tried running the viewer (calling the same service) both as localhost and on a production server. Both result in the same error.
The widget .xml is pretty simple but I can confirm that it is pointed to the task, not just the gp service itself, as is directed by the Clip and Ship tutorial.
<?xml version="1.0"?>
-<configuration><dataextractionservice>http://wap01512:6080/arcgis/rest/services/ExtractDMMnew/GPServer/ExtractDMM_new</dataextractionservice><aioselectionmethod>draw</aioselectionmethod></configuration
and the relevant portion of my config.xml is as follows:
<widgetcontainer layout="float">
<widget url="widgets/DataExtract/DataExtractWidget.swf" config="widgets/DataExtract/DataExtractWidget_3.xml" label="Data Extract" icon="assets/images/i_scissors.png" preload="open"/>
</widgetcontainer>
I've looked all over the tag reference but don't see any way to set the output location in the widget configuration.
I don't have a publicly available viewer with the widget in it at the moment but the REST service for the Clip and Ship is available here:
Task: ExtractDMM
My question is whether the failure is a function of the gp model/service (I don't think so) or of the viewer config or perhaps a folder permissions issue on the server. I'm grateful for any suggestions.