A TimThumb error has occured

The following error(s) occured:

The remote file is not a valid image. Mimetype = 'text/html' File = /var/www/html/timthumb/cache/timthumbeTo2rP

Query String : h=338&src=http%3A%2F%2Fimg.campeggi.com%2Fphotogallery%2Fmid%2F01_9431.jpg&w=438&zc=1
TimThumb version : 2.8.13