My advice would be to avoid that bike. It has low end components (RST fork, Gears etc) that won't stand up to dirt jumping for long. Normally it's the thing you least want to break that goes first. Cheaper components just aren't worth it with that kind of mountain bike discipline. Save some more money and go for something a little more robust like
http://www.konaworld.com/08_shred_w.htm. It has a good frame and fork and you can upgrade the rest of the components as and when you ability/budget allows.