[Plugin: Feed Pull] Having difficulty forming a proper xPath

Here’s a link to the xml I’m trying to import:

XML

I’ve tried many combinations of /ATSFeed/ArrayOfShows/Show, but all I’ve seen so far is “Warning: no items in feed”. I’m guessing it may have something to do with the custom namespace, but it’s hard to know for sure when nothing I enter under “xpath to posts” seems to make a difference. Any advice/guidance here would be greatly appreciated.