Hmmm, don't quite know what you're doing wrong, and this will be a completely unhelpful posting, but I don't see why people have so many problems flying kites, jumping etc. Within a couple of hours of flying my first kite (2.8m Predator Mk II) I was doing some fairly big jumps, and then I got a 4.9m Blade and was soon doing jumps that were quite a bit bigger... Not once have I had even a slightly heavy landing... I just kind of float back down. I don't take any special precautions now either, I usually do it bare footed on the beach, and even on tarmac when showing people my kite (I don't do big jumps over tarmac though). I've managed to jump over my transit van too, which I thought was pretty cool...
The only advice I can give you is to do it over soft sand if you keep getting hurt unitl you have perfected the art... Maybe your brake lines are too long too, if you shorten them, you'll stop the kite from overflying and luffing...just a suggestion.... BTW I've also jumped with 5.7m Waterfoil, 7.2m Blade, Wipikas, Spider Modulus (in strong winds), Airea raptor, 7m Advance Tethis and various size C Quads....so its not the kite....although, the Blades and Predators were the easiest.
Check my website for some photos if you like.
http://website.lineone.net/~justal/WebPage
