A TimThumb error has occured

The following error(s) occured:

The remote file is not a valid image. Mimetype = ''E:\Website\Dvbcn\wp-content\themes\skin\cache\tim3C19.tmp

Query String : src=http://vod.dvbcn.com/image/cover/D488EECA89BD497A8EB8D60F4868E3AF-6-2.png&h=428&w=760&zc=1
TimThumb version : 2.8.13