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\tim941A.tmp

Query String : src=http://vod.dvbcn.com/6b6b0e87f9c24a598912bb42989e799f/covers/776875d6d57245418e34388f4911f576-00004.jpg&h=428&w=760&zc=1
TimThumb version : 2.8.13