The requested URL /devhttp://www.livingthreadstextileartists.com/dev/images/artists-images/jeanallton.jpg was not found on this server.
Please take a look at the URL because obviously the /dev is appended to the target URL.
Here is the script causing the issue:
function updateImage (imageLocation)
var url = 'http://www.livingthreadstextileartists.com/dev' + imageLocation;
document.getElementById("frameID").src = url;
You should remove the "dev" in the var url.... statement.