Making A .JPG Background Transparent

I followed these two direction Making the background of an image transparent in Gimp and Gimp Tutorial – How to make an image background transparent

You can find the image here on Bing Images. The trouble I'm having is it will not export to a .png withn or without changes. I have Gimp 2.8.10. Can anyone help explain as to why I can't export this image?

Thanks!...