Hi Caryn,
Yes, the file seems fine. Try this:
1) Delete it from wp-content/updraft.
2) Press the "rescan" link in the "restore" section. It should then disappear from the list of what's available.
3) Rename the file, taking out almost all of that middle section. e.g. Something like:
backup_2013-08-01-0822_Testing_d4a1174f6109-themes.zip
The rest of the filename needs to remain as-is - that's used.
4) Put it in wp-content/updraft, and press "rescan" again (or use the drag/drop uploader).
Then see if that has a different result...