Your comments

Answered my own question - I hadn't actually created a Playlist!  Also the username was timbrass which I found by looking at the URL of one of my videos - the G+ upgrade hides this!

According to Martin, it looks like some YouTube feeds won't work if they contain copyright material....

Works on Standard Template but not on the new ZipApp template.  On standard template you get the back button on each article

I have seen the same on an App that only has Twitter feeds.  The App is blank the second time you run it.

You get that error in VS if you forget to unzip the file downloaded from ZipApp - you need to "Extract All" before starting the App.  My bad!

Works when I move the images to a Wordpress library....

Specifically settings for BacgroundHead, BackgroundTitle, BackgroundShim, the <body> Background and the colours for the Backbutton...

Looks like the path that ZipApp creates does not point to the images directory holding the files - there is an upper case "Images" in the error string rather than "images" - is that the problem?