One additional note. I did start the repository browser from a working copy and I wanted to clarify this because it is documented at the bottom of this page [1] that the webviewer-enabled context menu items will not function if the repository browser is started outside a working copy and by entering a URL.
If I start the repository browser outside a working copy, the webviewer-enabled context menu items are not present.
[1]
http://tortoisesvn.net/docs/nightly/TortoiseSVN_en/tsvn-dug-repoviewer.html