sub-categories not importing

I’ve just imported a WP blog’s content via the xml file into a test site. Everything works great, but for some reason the sub-categories are not working properly. Under EDIT, I can see the posts listed with the proper categories and sub-categories attached. But when I filter by the sub categories, there are none listed. In the list of categories, it shows 0 entries for the sub-categories, despite the fact that I went in and hand-tagged one of them just to run a test.

Has anyone seen this before? Any ideas what might be causing it, and how to fix it?

Thanks!