It's me again. I figured out what I did wrong. I forgot to turn the list items into links! Sorry!
My bigger mistake was trying to follow David Powers' instructions from memory. Big mistake at my age.
That one question remains however - is there anything inherently navigational about a nav element? Or is it simply a div by another name?
A <nav> element is simply a <div> with a different name.
The same is true of <article>, <section>, <aside>, <header>, and <footer>. The difference is that the new HTML5 elements describe the role of the element in the structure of the page. They're mainly useful for search engines. Assistive technology for the blind will eventually also make use of the different elements, making it easier for disabled people to find important parts of the web page.
Another feature of <nav>, <article>, <section>, and <aside> is that they're known as "sectioning elements". Browsers will eventually be able to use sectioning elements to generate an outline of the page's contents. Other elements, such as <div> and <header> won't be included in the outline.
David, thank you for your constancy. Much appreciated.