I realized that the ref/@targets in the site map, which pointed to the HTML pages, were technically incorrect. They pointed to the pages as if they were in the same directory, not two levels up. After working on it for an hour in the lab, I got home and realized the solution was fairly simple: add '../../' to the @target when generating the site map, and then in the XHTML5 generation (since it relies on the @target for filenames/locations, etc) pre-process the site map so that all @targets are stripped of their path. I decided to add the final few people that were missing; one was a misspelling and the other 3 are unidentified (but likely also misspellings, which I've noted in the notes). Graves is now passing the diagnostics.