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/timthumbss34Xv

Query String : a=c&h=240&s=1&src=http%3A%2F%2Fwww.campingitalia.it%2Ffoto_%2Fplanimetrie%2F261.jpg%3F3143135228&zc=1
TimThumb version : 2.8.13