Don't feel bad. That is a wicked hard technique and I'm not close to mastering it yet either. I go fingerstyle, using my thumb on the roots and then staggering index and middle for the "galloped" octaves. But I'm not close to getting it up to speed with any accuracy yet.
That being said, it sounds to me like the original Donna Summer version was recorded with a pick (as a lot of those disco standards were), which to me is an even more astounding display of technique.
BTW when you get "Hot Stuff" down you can move on to this: http://www.youtube.com/watch?v=FOx81aG-EN4
The incomparable Bernard Edwards. Check out the intro, and at the 3:00 mark for plenty of galloped-octave goodness.