When I click on the Audio, Video, Photography link, I get no posts, only the Welcome line by dkmarsh.

Okay, I got it. Never mind. I had to change the date of posts drop down menu.

So do I, and the reason is that (y)our Display Options setting (below that missing thread list) is for a period short enough for the latest post in that forum not to show up. I suspect your setting is the default (active in the last month), while the latest post there was made on August 5. Just select another view period in the Show Topics pull down menu and hit the Change button below.