[Foozle]

You don't have your links setup correctly. First, remove the xmlns tags in the links (xmlns="" – remove these). Second, you need to point the links to the correct items. rn1 and rn3 (instead of n2 and n4). Third, your footnotes need to have an anchor name instead of a link ref (a name="ch001.xhtml#rn1" and "...rn3").