Here's another vote blaming the hangers, not the sporran. That being said, I have to also point out that there are a few different kinds of sporrans. There are only really three styles in general ('day-wear' pouch type sporrans, 'formal' or 'hunting' sporrans, and the 'Rob Roy' bag type), but I make a dozen or so variations and styles myself, so it may just be a matter of the style of sporran as much as the faulty nature of the hangers.

One problem with the hangers or suspenders is that they focus all of the weight of the sporran right on the front of the belt, which is really just going to make everything that much heavier. You'll be far better off with a proper strap, either leather and chain, or plain leather. My preference is for the leather and chain, as I find it tends to 'move' better while walking...