Not importing XML - 'No new nodes'

I am submitting a new issue after following the suggestions posted on https://drupal.org/node/1189682 to no avail.

I am getting the 'No new nodes' message when importing an XML file to create new nodes. The file does contain new data, has the correct UTF-8 encoding, and does not have incorrect linefeeds. The import has worked in the past, but after updating either Drupal core or a contrib module, it has not worked and I do not recall after which update it started to fail.

Here is my current setup of Drupal with relevant modules.

Drupal 7.23

Modules:

Feeds 7.x-2.0-alpha8
Feeds Tamper 7.x-1.0-beta4
Feeds XPath Parser 7.x-1.0-beta4
Entity API 7.x-1.2
Entity reference 7.x-1.0+8-dev (2013-Jul-30)

Patches:

Feeds Tamper
- feeds_tamper_ui/feeds_tamper_ui.module
- See https://drupal.org/node/1794482#comment-7737375
- a UI patch, should not affect the import itself

I am attaching a sample XML file containing a single item.

In the import I have used both the file upload and local directory to submit the file; for the node processor settings, I have tried replace, update, and do not update existing nodes; skip hash check enabled and disabled, and am using Tamper to map number ID numbers in the XML to node IDs.

Not sure if there is any more info I need to provide - just ask and I will do so.

Thanks much,
Eric